Female scientific talents constitute a critical force in the field of inorganic non-metallic materials, having made remarkable contributions to disciplinary development. This paper examines the status and challenges faced by female researchers in project applications, research funding, and career advancement by analyzing supporting policies implemented by the inorganic non-metallic materials discipline (hereinafter referred as “the discipline”) under the national natural science foundation of China (NSFC) in recent years. Here the paper evaluates the effectiveness of these policy measures in promoting the growth of female scientific talents, thereby providing empirical support for the discipline policy making and the sustainable development of outstanding female researchers. Looking ahead, the discipline will intensify efforts to cultivate female reserve talents, continuously advance the reform of the science funding system, and enhance the innovative contributions of female researchers to China’s scientific self-reliance and technological independence in the inorganic non-metallic materials domain.

IntroductionThe complexity of lithium iron phosphate waste sources dictates the intricate composition of the solution after acid leaching. Particularly during the pretreatment process, lithium iron phosphate waste can become mixed with anode materials and may contain trace amounts of nickel, cobalt, and manganese. Therefore, in addition to the characteristic impurities of lithium iron phosphate, such as iron, aluminum, and phosphate, the acid leach solution obtained from lithium iron phosphate waste through high-pressure oxidation leaching is typically accompanied by small amounts of copper, nickel, cobalt, manganese, fluorine, and other impurity elements. On one hand, regarding product purity, if these impurity elements are not adequately removed, they may lead to the deterioration of lithium carbonate quality, adversely affecting subsequent processing. On the other hand, considering recycling value, metals like copper, nickel, and cobalt have significant market value, necessitating their recovery to improve the economic viability of the entire process.MethodsRemove Cu, Fe, Al, P, Ni, Co, Mn and other impurities by chemical method. Removal of calcium impurities by HP4040 resin. The adsorption process of Ca2+ was correlated using kinetic equations, confirming that the adsorption process of HP4040 resin for calcium removal aligns more closely with a pseudo-second-order kinetic model. This indicates that the adsorption reaction between calcium ions and the resin is predominantly governed by chemical adsorption. Thermodynamic analysis revealed that the adsorption process of calcium ions on the resin conforms to the Langmuir isotherm model. Removal of fluorine impurities by modification of MgO-modified -spodumene, both pseudo-first-order and pseudo-second-order kinetic equations were employed to describe the adsorption of fluoride ions onto the adsorbent. The fitting results suggest that the fluoride adsorption process largely adheres to the pseudo-second-order kinetic model. Thermodynamic analysis further indicated that the adsorption of fluoride by the defluorination agent aligns better with the Langmuir model, suggesting a preference for monolayer adsorption.Results and discussionThe main conclusions of this study are summarized as follows. This research systematically investigates the purification and decontamination processes of waste LiFePO4 lithium-containing leach solutions, focusing on the reduction and removal of copper, neutralization of iron, aluminum, and phosphorus, alkalization for nickel, cobalt, and manganese removal, resin-based calcium removal, and adsorption for fluoride removal. The distribution of impurity ions in the acid leach solution, including Fe, Al, Cu, Ni, Co, Mn, Ca, and F, has been analyzed throughout the decontamination process, and the entire flow of acid leach solution decontamination has been experimentally validated. The findings are as follows: To effectively reduce and remove copper, the optimal addition of iron powder is 1.1 times the theoretical amount, achieving a recovery rate of 99.95% and a copper sponge purity of 95.02%. For neutralization to remove iron, aluminum, and phosphorus, the optimal reaction conditions are a temperature of 30 ℃, an endpoint pH value of 4, and a reaction time of 30 min. Under these conditions, the impurity elements Fe, Al, and P are predominantly removed, while the loss of valuable metals like Ni, Co, and Mn is minimal. In the alkalization process for removing Ni, Co, and Mn, precipitation occurs at pH 12, with precipitation rates exceeding 99.5% for all target metals. The resin-based calcium removal process studies and compares the advantages of three commercially available calcium removal resins, ultimately selecting HP4040 resin, which demonstrates a maximum adsorption capacity of 35.28 mg/g for calcium, achieving over 91.6% single-stage calcium adsorption. Meanwhile, the synthesized MgO-modified - spodumene adsorbent material achieves a single-stage adsorption rate of over 85.8% for fluoride, providing a pathway for developing low-cost deep fluoride removal materials.ConclusionsThis study systematically investigates the purification and decontamination process for waste LiFePO4 lithium leach solutions. After the reduction to remove copper, neutralization to eliminate iron, aluminum, and phosphorus, alkalization for nickel, cobalt, manganese removal, resin-based calcium removal, and adsorption for fluoride removal, the purification of the liquid obtained allows for lithium carbonate recovery.

IntroductionChina is a large country in the photovoltaic (PV) industry, with a vast amount of end-of-life (EOL) PV modules requiring proper management. However, encapsulants (EVA) and fluorine-containing backsheet (TPT) in PV laminates, as high molecular weight organic polymers, impede subsequent PV recycling processes. Pyrolysis is an effective means for recycling end-of-life PV laminates by removing the EVA and TPT. However, in practical pyrolysis processes, EVA and TPT are inevitably co-pyrolysis together. Due to variations in manufacturing methods, the proportion of organic components differs among PV laminate models, potentially affecting their co-pyrolysis behavior—A topic that remains underexplored. This study focuses on investigating the co-pyrolysis characteristics and mechanisms of EVA and TPT at different mixing mass ratios. Kinetic modeling was employed to analyze the heat loss behavior and determine the co-pyrolysis mechanisms.MethodsThe EVA hot melt adhesive used in the experiment was sourced from Jiacheng Plastics Co., Ltd (China) with a particle size lower than 100 mesh. The TPT was obtained from Youdisheng Electronic Materials Co.,Ltd (China). The TPT was crushed, ground, and sieved to pass through a100 mesh standard sieve, and then dried in an oven at 60 ℃ for 12 h. The mixing mass ratios of EVA and TPT were determined to be 5 : 1, 3.4 : 1.0, and 2 : 1 through literature research and experimental validation.A thermogravimetric analyzer (TG, STA 449 F5 Jupiter, NETZSCH) was used under an argon atmosphere with a flow rate of 50 mL/min. Samples of (10.0 ± 1.0) mg of EVA, TPT, and different ratios of their mixtures were placed in crucibles. The samples were heated from 50 ℃ to 800 ℃. Based on an extensive literature review, the heating rates of 10, 15, 20 ℃/min, and 25 ℃/min were selected. The synergistic effect was characterized using the difference between the theoretical and actual degrees of pyrolysis (W) to investigate potential pyrolytic interactions during the co-pyrolysis process. The Flynn-Wall-Ozawa (FWO) method and the Kissinger-Akahira-Sunose (KAS) method (Model-free method) were employed to calculate the activation energy, and the Coats-Redfern (CR) method (Model-free method) was chosen to ascertain the pyrolysis reaction mechanism.Results and discussionThe co-pyrolysis weight loss was divided into two stages, the first stage was treated at 300-380 ℃, which was mainly due to the deacetylation of EVA to produce acetic acid. The second stage was at 380-510 ℃, corresponding to the degradation of EVA and TPT long chains. At 800 ℃, the co-pyrolysis of EVA and TPT with the ratio of 2 : 1 resulted in a total weight loss of approximately 94.5%, while ratios of 3.4 : 1.0 and 5 : 1 achieved higher total weight losses of 96.7% and 97.9%, respectively. As the proportion of TPT decreased, the total weight loss ratio of the mixture gradually increased, which may be due to the presence of PET in TPT. The presence of benzene rings in PET caused cross-linking of the product, generating more polyaromatic hydrocarbons and promoting coking. The overall synergistic interaction between EVA and TPT during co-pyrolysis was antagonistic effect. The antagonistic effect was most pronounced when the ratio of EVA to TPT was 2 : 1, probably due to the increase in TPT, which made the coking more pronounced. The average activation energy of co-pyrolysis was higher than that of EVA and TPT pyrolysis alone, suggesting that more energy was required for co-pyrolysis, further supporting the antagonistic effect of co-pyrolysis. The average activation energies were 244.7-245.5, 239.6-240.1 kJ/mol and 261.2-262.8 kJ/mol for EVA and TPT mass ratios of 2 : 1, 3.4 : 1.0 and 5 : 1, respectively. In order to further determine the reaction mechanism of the co-pyrolysis, the reaction mechanism of the co-pyrolysis process was explored using the CR method. The co-pyrolysis followed the diffusion controlled D5 model, D3 model, and D6 model for EVA and TPT mass ratios of 2 : 1, 3.4 : 1.0 and 5 : 1, respectively. Changes in the mechanism functions of different ratios of co-pyrolysis further indicate the influence of the mass ratio of EVA and TPT on the interactions.ConclusionsIn this paper, the pyrolysis behaviour, kinetics and reaction mechanisms involved in the co-pyrolysis of EOL PV laminates at three mass ratios (2 : 1, 3.4 : 1.0 and 5 : 1) of EVA and TPT were investigated, and key findings are as follows:1) The main pyrolysis happens between 300 ℃ to 510 ℃. As the proportion of TPT decreased, total weight loss increased. Specifically, the weight loss rose from 94.5% to 97.9% as the EVA : TPT mass ratio increased from 2 : 1 to 5 : 1.2) The degree of synergistic interaction varied with mixing ratio. TPT promoted char formation and reduced overall pyrolysis efficiency, particularly at the 2 : 1 ratio, where its proportion was highest. This antagonistic effect was reflected by an average activation energy of 245.1 kJ/mol.3) Coats-Redfern (CR) model fitting revealed that the co-pyrolysis of EVA and TPT followed diffusion-controlled mechanisms. The reaction models corresponded to D5, D3, and D6 for the 2 : 1, 3.4 : 1.0, and 5 : 1 ratios, respectively.This work provides mechanistic insights into the co-pyrolysis behavior of key organic components in PV laminates and offers theoretical support for the development of thermal recovery methods for waste PV modules.

IntroductionTo enhance the lithium leaching rate, carbon thermal reduction can be employed to convert lithium into lithium carbonate, thereby enabling selective recovery through water leaching. However, due to the relatively low solubility of lithium carbonate, it is challenging to significantly improve the efficiency of water leaching. Furthermore, the extent of carbon thermal reduction is highly dependent on factors such as the amount of added carbon source, reaction temperature, and reaction time. Consequently, there is an urgent need for advanced technologies that are characterized by low energy consumption, a simplified process, and high efficiency for the recovery of active cathode materials from spent lithium-ion batteries. While traditional metallurgical recovery processes can effectively extract most valuable metals from cathode waste, the current lithium extraction process typically requires multi-stage extraction or stepwise precipitation to produce lithium carbonate. This results in a lengthy back-end lithium extraction process, with intermediate steps prone to lithium metal loss, leading to a recovery rate of only 60% to 80%. In the context of comprehensive utilization recycling technologies, efficient lithium extraction and selective leaching of target elements remain bottleneck issues. To address the challenge of efficient lithium extraction, this study proposes the use of waste ternary positive and negative electrode mixed materials as raw materials, employing a process flow of "reduction roasting for priority lithium extraction" followed by water leaching and acid leaching to comprehensively recover valuable metals from the waste.MethodsWeigh accurately an appropriate amount of experimental raw materials and transfer them into a mortar for thorough grinding. Subsequently, transfer the ground materials into a corundum crucible. Place the crucible containing the raw materials into a tube furnace for roasting. Prior to initiating the program, introduce argon gas at a flow rate of 200 mL/min for 30 min to ensure an inert atmosphere. Heat the materials at a controlled heating rate of 5 ℃/min until reaching the set temperature. Once the temperature naturally decreases to room temperature, carefully weigh the mass of the roasted product and record the mass difference before and after roasting. Transfer the roasted product into a beaker, add pure water at a liquid-to-solid ratio of 80 mL/g, and stir using a mechanical stirrer at a constant speed of 500 r/min. Systematically investigate the effects of roasting temperature (500-700 ℃), roasting time (30-150 min), and stirring time (water leaching time of 2-10 h) on the leaching rate of lithium. Calculate the mass differences of various elements based on the recorded mass differences of the roasted products before and after treatment, combined with the leaching efficiency.Results and discussionUsing the positive and negative electrode mixtures from waste lithium-ion batteries as raw materials, lithium was selectively extracted via an in-situ reduction roasting-water leaching process without requiring additional reagents. Single-factor experiments were conducted to determine the optimal process conditions, which were identified as a roasting temperature of 600 ℃, a roasting time of 30 min, and a stirring time of 4 h. Under these conditions, the leaching rate of Li reached 72.23%, while Ni, Co, and Mn exhibited negligible leaching. The elemental contents before and after carbon-thermal reduction were quantitatively analyzed using SEM-EDS. In conjunction with ICP-OES detection results, it was determined that the raw materials contained impurities such as Al, F, and P. Carbon-thermal reduction reactions of commercial ternary cathode materials free of impurities were performed under identical conditions. The leaching rate of Li from the pure ternary material reached 96.6%, significantly higher than that achieved with impure materials (72.23%). Roasting products under various conditions were characterized by X-ray diffraction. It was observed that as the roasting temperature increased from 500 ℃ to 600 ℃, the characteristic peaks of NCM disappeared, indicating the complete destruction of the NCM (LiNixCoyMn1-x-yO2) crystal structure. The resulting roasting products primarily consisted of Li2CO3, Co, Ni, CoO, NiO, and unreacted graphite.ConclusionsThe optimal process were identified to be roasting temperature of 600 ℃, roasting duration of 30 min, and stirring time of 4 h, through single-factor experiments. The lithium leaching efficiency of 72.23% was achieved, while nickel, cobalt, and manganese exhibited negligible dissolution. Notably, under identical conditions, commercially sourced pure ternary cathode materials demonstrated significantly enhanced lithium recovery at 96.6%, maintaining minimal co-leaching of transition metals (<0.5%). To optimize the comprehensive lithium recovery efficiency in spent lithium-ion battery recycling, strategic introduction of additives capable of exerting synergistic reduction effects during the carbon thermal reduction stage is proposed. Subsequent research should focus on systematic evaluation of additive economics coupled with rigorous quantification of their lithium extraction enhancement potential.

The rapid increase in demand for lithium-ion batteries (LIBs), driven by their widespread use in electric vehicles, consumer electronics, and energy storage systems, has led to a significant rise in the generation of waste LIBs. These batteries contain valuable metals such as lithium, cobalt, nickel, and manganese, which are essential for the production of new batteries. However, the disposal of these batteries, especially after their life cycle ends, poses substantial environmental and economic challenges. Traditional recycling methods, such as hydrometallurgy and pyrometallurgy, are effective in recovering metals from spent batteries, but they are hindered by high energy consumption, environmental pollution, and complex processing techniques. Consequently, more sustainable and efficient recycling technologies have become the focus of research, with direct regeneration techniques emerging as a promising solution to overcome the limitations of conventional methods.This review discusses the recent advancements in direct regeneration technologies for recycling the cathode materials of waste LIBs. Direct regeneration refers to methods that restore the electrochemical properties and structural integrity of degraded cathode materials, making them suitable for reuse in new batteries. These techniques are designed to enhance the resource recovery process by efficiently restoring the performance of the cathode materials while reducing environmental impact. Key methods under direct regeneration include electrochemical recovery, solid-state sintering, and hydrothermal regeneration. These methods have shown significant promise in improving material recovery rates and enhancing the economic feasibility of the recycling process.Electrochemical recovery methods involve using electrochemical reactions to selectively recover valuable metals from spent cathode materials while restoring their electrochemical performance. This process can be performed under relatively mild conditions, which significantly reduces the environmental impact compared to traditional methods. Solid-state sintering techniques, on the other hand, involve high-temperature processes that repair the crystal structure of the cathode materials, restoring their electrochemical stability and performance. Hydrothermal regeneration, a more environmentally friendly approach, uses aqueous solutions under high temperature and pressure to regenerate the cathode materials, making it a promising method for green recycling. All these techniques offer substantial advantages, such as reducing material loss, minimizing harmful byproducts, and enhancing the overall efficiency of the recycling process.While these methods have demonstrated considerable potential in laboratory settings, there are several challenges that must be overcome to scale these technologies for industrial applications. One of the primary barriers to the widespread adoption of direct regeneration methods is the high cost of reagents and the energy requirements of some techniques, which make them less economically competitive with traditional recycling methods. In addition, the complexity of controlling reaction conditions and maintaining consistent material quality during large-scale regeneration processes poses significant challenges. Furthermore, ensuring that the regenerated materials meet the stringent performance standards required for new, high-performance batteries is a critical issue that needs to be addressed.Despite these challenges, direct regeneration technologies offer a viable alternative to conventional recycling methods, with the potential to significantly reduce reliance on raw material extraction and minimize the environmental footprint of LIBs. The main advantage of these technologies lies in their ability to restore cathode materials to their original or near-original performance levels, thus extending the lifecycle of valuable materials. This ability not only helps conserve resources but also reduces the environmental damage associated with the mining and processing of raw materials.Summary and prospectsDirect regeneration technologies for LIB cathode materials have shown significant promise in recent years, offering an environmentally friendly and resource-efficient alternative to traditional recycling methods. However, for these technologies to be successfully implemented on a large scale, several challenges need to be addressed. High processing costs and energy consumption, the need for better control over reaction parameters, and the integration of regeneration techniques into existing recycling infrastructures are the key hurdles that need to be overcome. Additionally, ensuring that regenerated cathode materials maintain their long-term stability and performance is crucial for their commercial viability.The future of LIB recycling will likely focus on optimizing these direct regeneration methods to improve their scalability, reduce costs, and enhance their overall efficiency. Research should prioritize the development of more cost-effective reagents, energy-efficient processes, and technologies that can be easily integrated into current recycling systems. Additionally, innovations in material science, particularly in the design of more durable and stable cathode materials, will play an important role in enhancing the regeneration process. As these technologies continue to mature, they will contribute to a more sustainable and circular economy for LIBs, reducing the need for new mining activities and minimizing the environmental impact of battery disposal.Ultimately, the successful development of direct regeneration technologies will help bridge the gap between the growing demand for LIBs and the need for sustainable resource management. By improving the efficiency and reducing the environmental impact of recycling, these technologies have the potential to make a significant contribution to the sustainable development of the battery industry, supporting the long-term goals of reducing carbon emissions and conserving valuable resources.

With the rapid development of portable electronic devices and electric vehicles, the production and demand of lithium-ion batteries (LIBs) have increased exponentially. Due to the limited life of LIBs, a huge amount of spent LIBs will inevitably be produced in the next 10~20 years. Efficient and clean recovery of spent LIBs is significant for resource recycling and environmental protection. In the recovery process, the cathode active material containing valuable metals must be separated efficiently from the Al foil collector. This procedure is a crucial link to reduce the difficulty of subsequent metal extraction and to achieve resource recovery. However, the organic binder polyvinylidene fluoride (PVDF), due to its strong adhesion and stability, has become a critical factor hindering the separation of cathode active materials. Currently, the methods for separating cathode active materials from Al foils can be classified into physical, thermal treatment, solvent dissolution, and electrochemical methods. The physical methods include mechanical crushing and grinding. The active materials separate when the cathode is exposed to mechanical forces in a shredder or impact/shear crusher. However, using mechanical crushing or conventional grinding methods are difficult to remove the organic binders on the active material surface only by mechanical force.Depending on the difference in thermal stability of the PVDF, Al foil and the active material, melting or degrading the PVDF binder on the surface of the cathode material can be used to separate the cathode active material. Direct calcination of PVDF is prone to pollutant emissions, and the pyrolysis process using a fully enclosed environment allows for better control and treatment of pollutant gases. Meanwhile, alkaline calcium oxide can accelerate the catalytic degradation of PVDF and enable the in-situ capture of inorganic fluoride. Apart from direct calcination / pyrolysis, new technology, such as molten salt-mediated treatment, can achieve the melting or degradation of PVDF in solid thermal media, detaching the cathode material from the Al foil and preventing the release of fluoride.Traditional strong polar organic solvents such as NMP, DMF, etc. can dissolve the binder by using the principle of similar solubility. However, the volatility and toxicity of these solvents are important obstacles to large-scale applications. The exploitation of organic solvents such as ethylene glycol and triethyl phosphate is expected to enable the replacement of highly volatile organic solvents. In addition, ionic liquids and deep eutectic solvents, as the new generation of green solvents, have shown potential for application in the separation of cathode materials. In addition to organic solvents, alkaline dissolution, oxidation by Fenton's reagent and electrochemical methods as representative of aqueous systems provide diverse options for the separation of cathode materials.Summary and prospectsIn summary, the current separation of spent LIBs cathode materials from the collector has made remarkable progress. In terms of overall effect, the current separation methods have successfully separated the cathode material from the collector Al foil, and the basic principles and process methods have been well investigated. However, analysis from a partial point of view, there are still some problems that need to be solved for different separation methods in terms of environment, economy and scale of use. Although the physical method has been widely used in industrial practice, problems such as low separation accuracy remain. The separation effect can be improved by the combined use of heat treatment method and physical method, i.e., the binder is removed by pyrolysis followed by crushing and sorting. This method achieves the separation of active materials from metal foils and substantially reduces the content of metal impurities in the active materials. However, this method is still difficult to achieve high-precision separation, and the development of more efficient physical separation methods and processes is still an important direction for future research. Compared with the physical method, the chemical method separates with higher precision. However, traditional chemical separation of active materials mostly uses toxic or volatile substances, with a high risk of secondary pollution. Fenton oxidation and supercritical fluid are green and environmentally friendly, but the high cost makes it difficult to industrialize and promote the application. The development of green, safe and low-cost solvents to achieve economic and efficient separation of active materials is another important direction that needs attention in the future.

Spent lithium-ion batteries contain rare metals such as lithium, cobalt, nickel and manganese, which are limited and unevenly distributed. Through recovery, we can effectively reduce the dependence on the exploitation of new mineral resources and realize the sustainable utilization of resources. It can reduce the cost of raw materials for the production of new batteries, and the development of the battery recycling industry can create new job opportunities and promote economic growth. As lithium-ion batteries contain heavy metals and other harmful substances, if discarded at will, these substances may seep into the soil and water sources, causing serious environmental pollution. The energy consumption in the process of battery production and recycling will produce greenhouse gases. If not handled properly, it may cause fire or explosion due to internal short circuit, overheating and other reasons, resulting in safety accidents. Therefore, effective recycling can reduce the energy consumption needed for the production of new batteries, thereby reducing greenhouse gas emissions. In terms of policies and regulations, many countries and regions have laws and regulations on e-waste disposal, which require the recycling of decommissioned batteries. Enterprises can show their sense of social responsibility and enhance their corporate image by recycling retired batteries. This can not only promote the development of related environmental protection technology and material science, establish a perfect battery recycling system, but also help to form a complete closed-loop industry chain from battery production to recycling. In a word, the recycling of spent lithium-ion batteries not only is of great significance to environmental protection and resource conservation, but also has a far-reaching impact on promoting economic development, meeting the requirements of laws and regulations, and promoting corporate social responsibility. With the popularity of electric vehicles and other portable electronic devices, the number of retired batteries will continue to increase, and the importance of battery recycling will become more and more prominent.Recycling the valuable metal resources of spent lithium-ion batteries can generate significant economic benefit. Among various recycling technologies, hydrometallurgy reveals better application potential due to its high maturity and recovery rate. This review focus on the development of hydrometallurgy, including the methods of leaching, separation, purification and re-synthesis of spent cathode materials. The first part introduces the leaching strategies, using acid, ammonia, deep eutectic solvent, bioleaching, and electrochemical leaching, as well as the auxiliary methods for such methods. The second part summarized the purification technologies for the leaching solution and the following re-synthesis process, while the former includes the chemical precipitation method, solvent extraction method, ion exchange method, and membrane separation method and the latter contains the high temperature solid state method and sol-gel method. In the thrid part, the bottlenecks of hydrometallurgy are summarized, and possible solutions are provided for the development of hydrometallurgy regeneration technology.Summary and prospectsHydrometallurgy has high efficiency and practicability in the large-scale application of recycling the cathode materials of spent lithium-ion battery. However, it consumes a large number of chemical reagents during the leaching process, generating pollutants and arousing attention. Therefore, the key issue is to reduce the negative environmental impact caused by hydrometallurgy. The selection of green and efficient leaching technology is beneficial to reduce the production of “three wastes” pollutants in the hydrometallurgy recycle technology, in which the environment-friendly organic acid has the characteristics of both leaching agent and chelating agent, promising to partly replace the inorganic acid leaching in the future. Using the microorganisms to leaches the spent lithium-ion batteries is an environmentally friendly and cheap method, which can design a targeted leaching process by adjusting its own redox properties. However, its strict cultivation environment and inefficiency have become a major difficulty in industrialization. Compared with the traditional acid leaching technology, deep eutectic solvent technology and electrochemistry technology still do not have the advantage in cost. For different cathode materials, auxiliary leaching methods such as mechanical activation, Fe ion medium and wave assistance can be adopted to reduce the amount of leaching agent, increasing the leaching efficiency and economic benefit. The traditional chemical precipitation and solvent extraction for separating and purifying often reveal a complex process, increasing the burden on the environment. The advanced purification technologies such as ion exchange and membrane separation generate positive effects on the environment, its cost still needs to be considered. Besides, enormous efforts have been paid on recycling the single cathode materials. However, the spent cathode materials collected from the market often consisted of a mixture of different cathode materials, which trend to increase the cost of pretreatment and separation process. Therefore, recycling technology for mixed cathode materials should be studied. For recycling other components used in lithium-ion batteries, such as anode materials, separator, current collector and so on, although it generates lower economic benefits than that of cathode materials, the closed-loop recycle of all components of spent lithium-ion batteries is still important in the future, which realizes high-value and deeply utilization of the whole components of spent lithium-ion batteries.

The pursuit of carbon neutrality has become one of global priorities, requiring the widespread adoption of electrification technologies across various sectors, including transportation, industrial processes, and residential applications. A critical factor in this transition is the integration of distributed energy systems that harness renewable energy sources, such as solar, wind, and hydroelectric power. These intermittent energy sources necessitate advanced energy storage systems to ensure a continuous and efficient energy supply. Among the various energy storage technologies under investigation, lithium-ion batteries (LIBs) have emerged as the most widely applied due to their high energy density, long cycle life, and scalability. However, the rapid growth in LIB ownership and demand has led to concerns about resource scarcity and the environmental pollution caused by spent batteries. Traditional recycling methods, such as pyrometallurgy and hydrometallurgy, although mature and widely used, suffer from several disadvantages, including high energy consumption, substantial pollution, lengthy processing times, and high costs. These limitations make them unsuitable for meeting the modern industry's demands for efficiency, economic viability, and environmental sustainability. Therefore, there is an urgent need to develop rapid, efficient, and environmentally friendly direct repair methods for battery materials.This review begins by examining the failure mechanisms of electrode materials and extends to the current advancements in electrode material repair methods. The failure mechanisms can be broadly categorized into active material degradation and interface reaction failures. Cathode materials, due to their higher recovery value, have attracted significant attention and research. The main recovery methods for cathode materials include solid-state sintering regeneration (SSR), hydrothermal regeneration (HTR), electrochemical regeneration (ECR), eutectic salt regeneration (ESR), and chemical lithiation regeneration (CLR). Among these, solid-state sintering and hydrothermal regeneration are the most technologically mature, with the highest industrial potential. However, both methods still require prolonged high-energy input, raising concerns regarding their economic and environmental sustainability. On the other hand, anode material recycling, driven more by the need to extract valuable metals than by economic incentives, primarily focuses on upgrading waste materials.Compared to traditional synthesis techniques, which suffer from high energy consumption and inefficiency, ultra-fast synthesis technology can instantaneously release large amounts of energy to quickly initiate chemical reactions. After the reaction is completed, energy input can be rapidly withdrawn to facilitate efficient cooling. This technology has attracted increasing attention in the materials synthesis field due to its efficiency and low energy consumption. The review then summarizes representative methods, including Joule heating, laser-assisted techniques, and microwave-assisted techniques, discussing their advantages, disadvantages, and applicability. It also analyzes the thermodynamic and kinetic differences between ultra-fast and traditional synthesis methods, emphasizing how ultra-fast synthesis breaks through conventional limitations by combining ultra-high temperatures with instantaneous reaction times. This approach provides new pathways for the novel synthesis of advanced functional materials, such as energy materials, high-performance catalysts and high-strength metal materials.Ultra-fast synthesis, with its low energy consumption and high efficiency, is rapidly becoming a critical breakthrough in the field of electrode material repair and regeneration. This review comprehensively outlines recent advancements in ultra-fast synthesis for both cathode and anode materials. Ultra-fast synthesis has successfully facilitated the regeneration of electrode materials such as LiCoO2 (LCO), LiFePO4 (LFP), LiNixCoyMn1-x-yO2 (NCM), graphite anodes, and silicon-based anodes. Despite the promising progress, challenges remain in scaling up ultra-fast synthesis for industrial applications. Precise control over energy input and product quality uniformity is crucial for industrial implementation. Moreover, the adaptation of ultra-fast synthesis to various material systems and a deeper understanding of the reaction mechanisms are ongoing research topics. The rapid development of artificial intelligence (AI) offers new opportunities for integrating AI into ultra-fast synthesis, enabling better process optimization and outcome prediction. In conclusion, ultra-fast synthesis represents a revolutionary approach in battery material repair and regeneration, offering a promising alternative to traditional recycling methods and supporting the transition towards a more sustainable energy future.Summary and prospectsThis review comprehensively summarizes the development background, application progress, and challenges faced in the recycling and repair of battery materials, with a focus on ultra-fast synthesis technology. Compared to traditional methods, ultra-fast synthesis has made significant advancements in the field of battery materials due to its speed, efficiency, and environmental sustainability. It has increasingly become the focal point of research. Meanwhile, the rapid development of artificial intelligence technology has provided strong support for deepening the understanding of the mechanisms behind ultra-fast synthesis, guiding its research direction, and improving its adaptability for industrial applications. Looking ahead, with the continued advancement of green low-carbon technologies and the growing demand for efficient recycling techniques, ultra-fast synthesis is expected to play a crucial role in promoting the recycling and utilization of battery materials, driving industrial upgrades, and providing key momentum for the sustainable development of the new energy industry through continuous innovation and optimization.

With the improved global wind power situation, the wind power industry is developing rapidly. Annual newly installed capacity in China increases steadily. To cope with the cost pressure of the low-price era in the wind power industry, wind turbines are continuously upsized, which has led to an annual increase in blade weight. As the early blades retire in large numbers, the non-degradable waste blades exert a tremendous pressure on the environment. This paper sorts out the key issues and challenges in the recycling of retired wind power blades. The current mainstream wind power blade recycling technologies are also listed, including mechanical recycling, thermal recycling, chemical recycling, and recyclable blade technologies. The differences among various recycling technology are analyzed systematically as well. From the perspective of the wind power industry and blade enterprises, it proposes development suggestions for recycling technologies, including blade extension, component recycling, and recyclable technologies.Summary and ProspectsAgainst the backdrop of global dual-carbon goals, the wind power industry is developing rapidly. Facing the environmental pressures brought by the increasing number of retired blades in recent years, there is an urgent need to develop low-cost, high-value, and low-carbon recycling technologies to overcome the challenge. The key scientific and technical issues causing difficulties in the degradation and recycling of retired blades mainly include a lack of technology for blades to serve beyond their designed lifespan, insufficient low-carbon material substitution technologies, and a scarcity of complete degradation and high-value recycling technologies. The key scientific and technical issues that make it difficult to degrade and recycle retired blades mainly include the lack of technology for blades to serve beyond their designed lifespan, insufficient alternatives for low-carbon emission materials, and a scarcity of fully degradable high-value recycling technologies. Mechanical recycling, thermal recycling, chemical recycling, and recyclable blade technologies are the current main recycling technologies. However, to meet the needs of blade life extension, the recycling of critical components, and complete blade recycling, relying on a single recycling technology is not sufficient. It is necessary to develop recycling technologies that can be used in combination for different purposes. In the future, the green, low-carbon, and high-quality development of the wind power industry can be promoted, and the rapid formation of new productive forces in China can be supported, through the development of systems for estimating the remaining life of turbines and blades, expanding the high-value application areas of retired blade components, exploring commercial recycling models for retired blades, developing next-generation blade technologies including recyclable technologies, and researching recycling and reuse technologies for retired wind turbines.

The global transition toward renewable energy and electric vehicles has triggered exponential growth in lithium-ion batteries (LIBs), resulting in a surge of retired batteries. As the predominant anode material in LIBs, graphite accounts for a significant mass proportion of batteries. However, improper disposal of spent graphite (S-Gr) through incineration or landfilling poses severe environmental risks, including particulate emissions and toxic residue release. Recycling S-Gr is critical to alleviating resource shortages, reducing production costs of high-purity graphite (which requires energy-intensive graphitization processes at 2500-3000 ℃), and achieving sustainable development goals. This review focuses on the failure mechanisms, recycling strategies, and reuse pathways of S-Gr, providing key insights for advancing closed-loop battery ecosystems.The degradation of graphite anodes during LIB cycling originates from multiscale failure mechanisms. Deterioration of the solid electrolyte interphase (SEI) caused by chemical decomposition, mechanical stress, and thermal instability leads to irreversible lithium loss and capacity fade. Concurrently, lithium dendrite growth on graphite surfaces increases internal short-circuit risks, while repeated Li+ intercalation/deintercalation induces microcracks and structural collapse of graphite layers. These coupled mechanisms initiate a vicious cycle of performance degradation, highlighting the necessity for tailored recycling approaches.Current recycling technologies focus on efficient separation and purification of S-Gr. Physical methods (e.g., flotation and sieving) achieve preliminary separation but suffer from impurity retention (purity <73.56%). Innovative techniques such as Fenton reagent-assisted flotation and pyrolysis-ultrasonic synergy enhance recovery efficiency, but face scalability challenges. Hydrometallurgical processes utilizing HCl, H2SO4, or organic acids (e.g., citric acid) effectively leach impurities like Li, Al, and Fe but generate corrosive waste. Pyrometallurgical approaches (e.g., inert atmosphere calcination and catalytic graphitization) restore graphite crystallinity but demand high energy consumption (>2600 ℃) and emit hazardous gases. Hybrid strategies combining hydrometallurgical treatment with high-temperature annealing emerge as promising solutions.Regenerated S-Gr demonstrates versatility in energy storage and functional applications. For secondary batteries, carbon-modified S-Gr via rapid thermal shock or phenolic resin coating exhibits superior performance in LIBs. In sodium/potassium-ion batteries, defect-engineered S-Gr shows enhanced kinetics and stability. Beyond energy storage, S-Gr can be transformed into high-value materials. Advanced applications include graphene production through lithium-intercalation exfoliation and catalytic composites for environmental remediation.Summary and prospectsDespite progress, critical challenges persist. The heterogeneity of S-Gr sources (natural, synthetic, or composite graphite) complicates standardized recycling. High costs, toxic emissions (e.g., fluorine), and intensive energy-consuming steps hinder process scalability. Future directions should prioritize intelligent sorting systems, AI-driven process optimization, and green alternatives like bioleaching. Integrating ultrasound, microwave, or electrochemical technologies could streamline processes and reduce energy consumption. Expanding S-Gr applications (e.g., flexible electronics, CO2 capture, and defect-engineered catalysts) requires interdisciplinary innovation. Addressing these issues will accelerate commercialization of S-Gr recycling technologies, promote sustainable battery ecosystems, and advance global carbon neutrality goals.

IntroductionThe advancement of solid oxide cells (SOCs) technology has led to a reduction in the operating temperature to 700-800 ℃, substantially enhancing the long-term stability of cells. However, as the temperature declines, the sluggish oxygen reduction/oxygen evolution reaction (ORR/OER) at the oxygen electrode emerges as a critical constraint on SOCs power output efficiency. (La0.6Sr0.4)0.95Co0.2Fe0.8O3- (LSCF), renowned for its excellent ORR/OER catalytic and electrical conductivities, is widely adopted in SOCs oxygen electrodes. However, its inherent drawback lies in the incompatibility of its thermal expansion coefficient (TEC) with traditional electrolytes like GDC and YSZ, often inducing fuel cell or stack failure during cycling due to thermal stress. To address this interface compatibility issue, combining LSCF with an electrolyte material, specifically Sm0.2Ce0.8O2- (SDC), to form a composite electrode proves to be viable. This not only mitigates the average TEC but also optimizes the reaction kinetics. In this study, LSCF and SDC materials were synthesized via the sol-gel method, and the impacts of varying SDC content in the composite electrode on phase structure, conductivity, thermal expansion, and ORR/OER performance were meticulously examined. Results indicate that SDC incorporation effectively curtails the material TEC, enhances ionic conductivity, and boosts ORR/OER activity. Ultimately, the LSCF/40SDC composite electrode manifests remarkable electrochemical performance and long-term stability in fuel cell and water electrolysis mode.MethodsA series of LSCF/xSDC composite electrodes were synthesized using the sol-gel method. Detailed structural analyses of the materials were conducted by X-ray diffraction (XRD). Electrical conductivity and thermal expansion coefficient of electrode strips were measured from room temperature to 800 ℃. Electrochemical impedance spectroscopy of symmetrical cells was performed, while the electrochemical performance and long-term stability of single cells were evaluated by electrochemical workstation.Results and DiscussionXRD results confirm pure phase LSCF and SDC were prepared via sol-gel method. LSCF exhibits a hexagonal perovskite structure, and SDC oxide adopts a cubic fluorite configuration. The composite powders exhibit only the characteristic diffraction peaks of LSCF and SDC, confirming their excellent chemical compatibility. The conductivity of LSCF/xSDC materials ascends steadily within 200-600 ℃. Above 600 ℃, the conductivity declines with the increasing temperature. Thermal expansion tests clearly demonstrate that combining strategy with SDC electrolyte markedly diminishes the TEC of LSCF electrode, achieving better alignment with the TECs of YSZ and SDC (10.5×10-6 K-1 and 11.4×10-6 K-1 respectively).Impedance analysis of symmetrical cells shows that increasing SDC content leads to a continuous reduction in polarization impedance. This stems from SDC-induced enhancements in material ionic conductivity and expansion of the electrode reaction three-phase interface, thereby improving oxygen catalytic capacity. The Distribution of Relaxation Times (DRT) outcomes for LSCF/40SDC at 650-850 ℃ signify that elevated temperatures notably propel each electrode reaction step, particularly influencing the oxygen surface and interface charge transfer processes.Electrochemical performance analysis of single cells indicates that a higher SDC proportion correlates with stronger oxygen electrode catalytic ability and improved cell performance, with the LSCF/40SDC cell exhibiting best performance. Moreover, composite SDC significantly boosts hydrogen production efficiency during water electrolysis, attributable to enhanced oxygen electrode OER activity and reduced electrode reaction polarization resistance. After 400 h of stable operation, the cell voltage diminishes marginally from 0.70 V to 0.68 V, yielding an degradation rate of 7.15%/1000 h The cell microscopic morphology remains intact, with tight cohesion among the oxygen electrode, isolation layer, and electrolyte without devoid of detachment or separation. La, Sr, Co, and Fe are uniformly distributed, with no interdiffusion or chemical reaction occurrences after the long-term test.Conclusion(La0.6Sr0.4)0.95Co0.2Fe0.8O3- perovskite and Sm0.2Ce0.8O2- powders were synthesized by sol-gel method, The effect of SDC content on material crystal structure, conductivity, thermal expansion coefficient, and electrochemical performance were investigated. The LSCF/40SDC material offers a superior TEC match with the electrolyte. In symmetrical cell tests, LSCF/40SDC presents the lowest polarization resistance and reduced activation energy. In full cell tests at 750 ℃, the peak power density surges to 1132 mW/cm2, 1.87 times that of the base LSCF electrode. During water electrolysis at 1.3 V, the full cell with the LSCF/40SDC electrode attains a current density of -875 mA/cm2. Notably, the LSCF/40SDC cell sustains stable operation for 400 h under 750 ℃ and 1000 mA/cm2 discharge conditions, with an ultra-low attenuation rate of 7.15%/1000 h epitomizing outstanding long-term stability.

IntroductionSolid oxide fuel cells (SOFC) is a device that converts chemical energy into electrical energy. Compared with traditional power generation equipment, SOFC has the advantages of flexible fuel use, no noise, low emission and high conversion efficiency. SOFC operates at high temperatures (600-1000 ℃) for a long time, due to the mismatch of Coefficient of Thermal Expansion between anode-electrolyte-cathode electrode, metal connector and sealing material and the combined effect of temperature gradient. Even if the stress caused by mismatching is not enough to cause structural failure in a short time, the battery running under such stress for a long time at high temperature will cause large creep damage to each component, and the initiation of cracks will cause SOFC leakage.The porosity of porous electrode is closely related to its thermal expansion coefficient, elastic modulus, Poisson ratio, material diffusion, electrochemical reaction, effective conductivity, and other parameters, which is the main factor determining the performance of key SOFC components. When hydrogen is first supplied to the battery, the anode material will change, as well as the porosity of the anode layer, leading to variation on its physical and mechanical properties, which can affect its structural integrity and reliability under long-term high-temperature service conditions. Therefore, it is of great significance to study the effect of porous electrode porosity on the creep damage of SOFC at high temperature.MethodsBased on the previous modeling and research of SOFC multi-physical field, the SOFC model of gradient pore anode under multi-field coupling is established. Then, according to the Wen-Tu creep damage model, the effect of anode porosity on SOFC creep damage was analyzed.Considering that COMSOL Multiphysics has good multi-physics coupling ability and ABAQUS has strong nonlinear analysis and module development ability, the research method of COMSOL-ABAQUS is adopted. Firstly, the non-uniform temperature field calculated by COMSOL was applied to the node of the ABAQUS finite element model as a thermal load. Based on the creep model of ductile exhaustion theory and the damage mechanics model of continuum, the ABAQUS creep damage subroutine was written, and the USDFLD subroutine was embedded to simulate the creep damage and crack propagation law of single-channel SOFC. When = 0.99 is defined, the crack initiation unit of the sample is regarded as the failure unit. According to the method proposed by Saanouni et al., the elastic modulus of the Gaussian point of the failure element is reduced to 1/106 of the initial elastic modulus, so that the subsequent stress of the point is approximately zero, indicating that the bearing capacity is lost here. By combining the high efficiency of COMSOL and the strong nonlinear convergence of ABAQUS, SOFC finite element model is established to analyze the creep damage and crack propagation law of a single planar SOFC element.Results and discussionCompared with the assumed uniform temperature field, the maximum equivalent stress of the upper connector, anode support, anode functional layer 2, anode functional layer 1, electrolyte, cathode and lower connector is 95%, 88%, 95%, 91%, 48%, 65% and 96% higher than that of the uniform temperature field, respectively. Therefore, the assumption of uniform temperature field is not accurate enough, and the real temperature distribution obtained under the coupling of multiple physical fields is needed to analyze the creep damage evolution of SOFC.The critical damage lifetime of SOFC connectors with gradient pore anodes is 31.4%, 26.4% and 17.9% longer than that of SOFC connectors with anode uniform porosity of 0.2, 0.3 and 0.4, respectively.Gradient pore anode design the upper connector of flat SOFC reaches the critical loss value at 64 kh, and the crack initiation, belonging to the surface crack, is located on the outer side of the 40 mm rib at the fuel outlet of the upper connector, and gradually expands to both sides. However, with the increase of time, the crack propagation rate gradually decreases, and the crack propagation almost stops at 80 kh. At this time, the crack length reaches a maximum of 32 mm, although it is a non-penetrating crack witch will not cause leakage, it is still a problem that cannot be ignored.ConclusionsThe main conclusions of this paper are summarized as follows: Compared with the assumed uniform temperature field, the maximum equivalent stress of each part of the flat plate SOFC under the coupling of multiple physical fields is higher than the predicted result under the uniform temperature field. The assumption that the uniform temperature field is not accurate enough requires the real temperature distribution obtained under the coupling of multiple physical fields to analyze the creep damage evolution of SOFC. At the same time, the critical damage life of SOFC connectors with gradient pore anodes is significantly longer than that of SOFC connectors with uniform anodes with different porosity. When the upper connector reaches the critical loss value, surface cracks are generated on the outer side of the fuel outlet rib of the upper connector and spread to both sides gradually, but with the increase of time, the crack propagation rate decreases gradually. Although it is a non-penetrating crack witch will not cause leakage, it is still a problem that cannot be ignored. This study shows that the gradient pore anode has potential advantages in long-term high temperature service and provides theoretical basis and data support for the structural integrity and reliability optimization design of SOFC structures.

IntroductionIndium tin oxide (ITO) film is an excellent transparent conductive material widely used in liquid crystal displays (LCDs), electroluminescent displays (EL/OLEDs) and various photovoltaic devices. In particular, heterojunction (HJT) solar cells have shown a broader development potential. In order to improve the photovoltaic conversion efficiency of heterojunction solar cells, transparent conductive films need to be deposited on curved or cylindrical solar collectors. The deposition of ITO conductive films on these non-planar substrates requires specially shaped ITO tubular targets as the deposition source. Therefore, the preparation of high-quality ITO tubular targets is a prerequisite for obtaining ITO films with excellent properties on curved or cylindrical substrates, and the shaping and high densification of ITO tubular targets have been a hot and difficult issue in this field. In this work, based on the theoretical model of binary particle grading and the composite spray granulation-cold isostatic pressing moulding process route, the effects of different grading ratios, moulding pressures, times and processes on the properties of powders, billets and targets were investigated.MethodsIn2O3 and SnO2 powders (purity 99.99%, Hunan Ruyang Ruijin Electronic Technology Co., Ltd.) were ball-milled at a mass ratio of 9:1 to formulate indium tin oxide powders with D50 (the particle size corresponding to the cumulative particle size distribution percentage of the samples reaching 50%) of 50 nm and 323 nm, respectively, and were mixed in accordance with different grade ratios. After mixing, anhydrous ethanol (analytically pure, Xilong Science Co., Ltd.) was added to disperse the powder in a ball milling tank, and the mass ratio of zirconia balls to powder in the slurry was 3:1, and the slurry was mixed and then milled in a planetary ball mill at 350 r/min for 8 h. The slurry was obtained at an inlet temperature of 190 ℃, with a slurry solids content of 60% (mass fraction) and 1.5% binder content, Spray granulation was carried out at a feed rate of 100 mL/h. The granulated powder was loaded into a cold isostatic pressing mould with an inner diameter of 6 mm and a length of 39 mm, and then fully vibrated and consolidated before bagging and sealing for vacuum treatment and cold isostatic pressing. The total holding time of the composite pressing curve was the same as that of the single-point pressing curve. The hollow tubular blanks were sintered in a tube furnace at a flow rate of 5 L/min in an oxygen atmosphere, at sintering temperature of 1550 ℃ and holding time of 8 h to produce ITO tubular targets.X-ray diffractometer (XRD, D8 Advance, Bruker) was used to study the phase structure. Scanning electron microscope (SEM, Tecnai-450, FEI) was used to observe the microstructure and elemental distribution with an operating voltage of 8 kV. The particle size distribution of the powders was tested using a laser particle size analyser model LS-609 from Omec. The loose packing density of the powders was tested using a WLD-02 Hall flow meter (funnel method). The density of ITO target was tested by Archimedes method and compared with the theoretical density to calculate the relative density of ITO target. The resistivity was measured by a four-point probe meter (MCP-T700, Mitsubishi chemical).Results and discussionBased on the tightest stacking theory model, the stacking density of ITO powder is significantly improved by binary particle grading, because a reasonable grading ratio can achieve the fine particles to fill the gaps between the larger particles, which effectively improves the loose loading density of ITO powder.The study of ITO tubular target prepared by cold isostatic pressing technology shows that the densification process of billet and target by forming pressure presents three-stage characteristics: Stage 1, the loose powder is rapidly rearranged under extrusion, with narrowing particle gaps and increasing bulk density, resulting in a lower resistivity; Stage 2, the resistance of internal friction between the particles increases, and the rate of densification tends to slow down; Stage 3, when the pressure exceeds the critical value (the limit), the particle plastic deformation or fragmentation occurs. deformation stress), the particles undergo plastic deformation or fragmentation, and the pores are further filled, but too high a pressure will form a pressure gradient due to the friction between the billet and the mould, which may, on the contrary, trigger internal slip leading to a decrease in density. The effect of holding time showed that within 5-11 min, extending the holding time significantly increased the relative density, which was attributed to the full displacement of the powder to fill the pores and the deformation of the particles, which increased the contact area and the interaction force; after more than 11 min, the pore filling tended to be saturated, and the density growth was stagnant. The composite pressing process effectively discharges the residual gas inside the billet through staged pressure release, eliminating the gas compression reaction force and achieving better densification results. The study reveals the key mechanism of cold isostatic pressure parameters on the microstructure regulation of ITO targets.ConclusionsIn this work, the effects of different grading ratios, moulding pressures, times and processes on the properties of powders, blanks and targets were investigated using a binary particle grading-spray granulation-cold isostatic pressing process. The results showed that particle grading improved the density of the powder, spray granulation improved the sphericity of the powder, and increasing the moulding pressure and prolonging the holding time improved the density of the billet. The billet with a relative density of 62.52% was prepared by the composite pressing process at a holding pressure of 200 MPa for 9 min, and the ITO tubular target with a relative density of 99.85% and a resistivity of 1.333×10-4 ·cm was obtained by sintering.

IntroductionFluorinated silane coupling agent was generated by reacting 2-(perfluorohexyl) ethyl methacrylate with trimethoxysilane, and then mechanically mixed with organic polysilazane (OPSZ) to obtain fluorinated modified OPSZ coating material. Finally, it was doped with micro nano SiO2 particles and a durable superhydrophobic coating was prepared using a spray coating method that is widely applicable to various substrates. The prepared superhydrophobic coating still has a water contact angle of over 150° after undergoing 360 cm (load of 50 g) sandpaper friction or 12 tape peeling tests (adhesion of 1.75 N/cm), and water droplets can roll freely like lotus leaf surfaces. This work provides a simple method for preparing hydrophobic/superhydrophobic coatings with excellent durability, and has potential applications in anti fouling, anti-corrosion, and other aspects.MethodsAccording to the National Standard of China GB/T 9286—1998 “Cross cut test for film of paint and varnish”, the adhesion of the coating to the substrate was determined by cross-cutting the film. According to the National Standard of China GB/T 6739—2006 “Determination of film hardness by pencil method for paint and varnish”, the pencil hardness of the prepared coating was determined using a QHQ-A pencil hardness meter. According to the National Standard of China GB/T 23989—2009 “Determination of solvent resistance wiping resistance of coatings”, the resistance to MEK wiping off the prepared coating was determined. Tape peeling and sandpaper abrasion were used to test the mechanical stability of the coating. The 3M tape (adhesive, 1.75 N/m) was pressed onto the coated surface for 30 s with a 100 g loading before being entirely peeled off. In this experiment, we designated the press-peeling procedure as one testing cycle. Every two press-peeling cycles, the WCAs and SAs of the coating were monitored to evaluate the coating/substrate interfacial adhesive strength between the coating and the substrate. A 25 mm × 25 mm coating loaded with 50 g weights was placed face-to-face with sandpaper (1500 grit) and pulled horizontally at a uniform speed for the sandpaper abrasion test. The WCAs and SAs of the coatings were measured to demonstrate mechanical stability after each 40 cm abrasion distance.Aqueous solutions of pH = 1, 4, 7, 10, 13 were configured using H2SO4 and NaOH, in which the coatings were placed for 24 h and 3.5% NaCl solution for 72 h to measure the WCA and SA values and to assess their resistance to acid and alkali corrosion and salt. The samples were exposed to UV light for 48 hours to assess weathering resistance.The self-cleaning properties of the coatings were tested by contaminant removal experiments on the coated surfaces using carbon black nanoparticles as contaminants. In addition, it was evaluated how well the coatings cleaned themselves after exposure to red wine, cola, fruit juice, tea, milk, and coffee.Results and discussionA durable high-hydrophobic coating based on Fluorinated silane coupling agent-modified OPSZ was designed and realized through a one-step synthesis method and spraying process, with a water contact angle of up to 115° and the coating hardness of up to 4H and excellent adhesion By adding micro-nano SiO2 particles, a superhydrophobic coating with a water contact angle of 156.3° and a rolling angle of 5.6° was successfully prepared. The superhydrophobic coating still had excellent hydrophobic properties after undergoing 12 cycles of tape stripping or 360 cm sandpaper rubbing test. This was due to the excellent anchoring characteristics of polysilazane and the excellent low surface energy of modified OPSZ, which resulted in good coating durability. After being doped with micro-nano SiO2 particles, a durable superhydrophobic coating was prepared using a spraying method commonly applicable to various substratesConclusionsThis coating has the advantages of low process cost and convenient operation and can be used to develop large-scale, durable superhydrophobic coatings with broad application prospects and practical value. In conclusion, this study provides a new solution for developing new superhydrophobic coatings.

IntroductionAlkaline environment-induced (Basalt fiber reinforced polymer) BFRP bars degradation is the prominent issues to BFRP-reinforced seawater sea sand concrete (SSSC) durability. A new type of basalt-carbon hybrid FRP (HFRP) bars was developed to improve the mechanical properties and durability of BFRP bars in marine environments. Herein, the effect of simulated SSSC pore solution alkalinity on the durability of HFRP bars was studied. Macro- and micro-properties of HFRP samples were tested, i.e., tensile properties, interlayer shear properties, microstructure, chemical composition, and chemical stability. Meanwhile, the degradation mechanism of HFRP bars in simulated SSSC pore solutions with different alkalinity has also been summarized. The results show that compared with BFRP bars, the initial tensile strength of HFRP bars has been significantly improved, and its interfacial strength has not weakened. After 90 d of corrosion, the increase in alkalinity leads to a maximum decrease in tensile strength and interlayer shear strength degradation of 19.67% and 23.43%, respectively. The degradation of HFRP bars includes fiber etching, resin hydrolysis, degradation of interfaces on fiber/resin and BFRP/CFRP. The smaller diameter and excellent corrosion resistance of carbon fiber, and BFRP/CFRP interface barrier function delay the penetration and corrosion of moisture and existing ions, i.e., Cl- and OH-, improving the durability of HFRP bars in high alkaline SSSC environments.MethodsTensile properties, interlayer shear properties, microstructure, chemical composition, and chemical stability of HFRP bars in simulated SSSC pore solution with different alkalinity were systematically measured. The research mainly adopts a combination of macroscopic performance testing and microscopic testing analysis.Both epoxy resin based BFRP and HFRP bars with a nominal diameter d of 10 mm were prepared by pultrusion process. HFRP bars consists of inner and outer cores made of CFRP and BFRP materials, respectively. The volume fraction of carbon fiber replacing basalt fiber was 25%.Three alkaline salt solutions with different pH values were designed to study the effects of simulated SSSC pore solution alkalinity on HFRP bars. The ordinary SSSC pore solution (Ca(OH)2 2 g/L, KOH 19.9 g/L, NaOH 2.4 g/L) was prepared from seawater with a pH value of 13.2. Two lower alkalinity SSSC pore solutions with pH value of 12.3 and 10.1 were diluted with artificial seawater, respectively. All corrosion exposure experiments were conducted in a constant temperature water tank at 55 ℃.The tensile performance was evaluated according to ACI 40.3R-12. The total length of the sample was 1000 mm, and the testing section was 10 d. The interlayer shear performance was determined based on ASTM D4475. The length and span of the sample were 7d and 6d, respectively. All experiments were conducted using MTS testing. The testing rates for tension and interlayer shear are 2 mm/min and 1.3 mm/min, respectively.Digital microscopy (DM) and SEM-EDS were used to analyze the corrosion morphology and composition of BFRP and HFRP bars after corrosion. AFM was used to analyze the microstructure of the transition zone at the BFRP/CFRP interface.Results and discussionThe macroscopic morphology analysis results indicate that the carbon fiber hybrid did not change the tensile line elastic failure mode and interlayer interface failure modes of HFRP bars. Compared to BFRP bars, the ultimate load of HFRP bars was increased, and the explosive fibers during failure were significantly reduced with the extension of corrosion time and the increase in simulated SSSC pore solution alkalinity; Both BFRP and HFRP bars interlayer interface failures involve a main crack that runs through and deviates from the BFRP/CFRP interface.The carbon fiber hybrid improves the tensile properties and interlayer interface properties of HFRP bars, and enhances its corrosion resistance in alkaline simulated SSSC pore solution. Taking tensile strength as an example, compared with BFRP bars, the tensile strength of BFRP bars in simulated SSSC pore solutions with pH values of 10.1, 12.4, and 13.2 was 78.48%, 71.20%, and 26.20% of its original value, while the corresponding values of HFRP bars were 87.86%, 85.22%, and 55.26%, respectively. After 90 d of corrosion, the maximum decrease in tensile strength and interlayer shear strength due to the increase in alkalinity was 19.67% and 23.43%, respectively.The degradation of HFRP bars in alkaline SSSC pore solution includes fiber etching, resin hydrolysis, and degradation of fiber/ resin interfacial and BFRP/CFRP interfacial properties. The smaller diameter of carbon fiber, excellent corrosion resistance, and BFRP/CFRP interface barrier function delay the penetration and corrosion of moisture and existing ions, improving the durability of HFRP bars in high alkaline SSSC environments.

IntroductionLightweight Ultra High Performance Concrete (LUHPC) exhibits attributes such as reduced weight, high strength, and minimal shrinkage. As a substrate for paving layers, the surface roughness of LUHPC is a critical determinant of interlayer shear resistance, tensile pullout resistance, and the prevention of early slippage and delamination. Notably, the lower surface hardness of gangue porous aggregates contributes significantly to the textural enhancement of LUHPC surfaces. The incorporation of steel fibers not only strengthens the internal bonding within the concrete but also influences the surface texture of LUHPC after roughening treatments. Despite existing research on the textural properties of pavement surfaces, there remains a gap in understanding the preparation of roughened interfaces for efficient application and the quantitative characterization of macro-micro texture characteristics and roughness influenced by steel fibers, which correlates with interlayer shear performance. While existing research has investigated the texture characteristics of pavement surfaces, there remains a critical need for further exploration into the development of roughened interfaces that facilitate effective implementation, a more detailed quantitative characterization of macro-micro texture and roughness, particularly under the influence of steel fibers, is necessary. Such investigations are crucial for establishing a robust correlation with the interlayer shear performance of heterogeneous paving materials. Additionally, Lightweight UHPC-high viscosity high elasticity binder-SMA specimens were fabricated to assess shear strength across different shot blasting intensities and temperatures. Linear regression analyses were conducted to model the relationships between macro-micro texture parameters and shear strength.MethodsThe surface roughness of gangue aggregate LUHPC was achieved through a shot blasting process, with three-dimensional texture data acquired via a handheld laser scanner. The point cloud data was processed using Gaussian filtering in MATLAB software to reconstruct the specimen's surface topography. Subsequently, both macroscopic and microscopic texture profiles of LUHPC were extracted utilizing a band-pass filter. The influence of steel fibers on the surface roughness of the specimen was assessed. An enhanced evaluation index, the Extended Tectonic Depth (ETD), was proposed, drawing upon the sand laying method's measurement principles. The correlations between macro-texture parameters (Ra, Rq, EMTD, EMPD) and micro-texture parameters (CMT, RMS) with ETD were analyzed. Furthermore, the relationship between shear strengths of the LUHPC-stress absorbing layer-SMA composite specimen and both macro- and micro-texture parameters was examined.Results and discussionAs the degree of shot blasting increased, the surface of LUHPC became rougher, the ETD grew larger, and the shear performance of LUHPC-high viscosity high elasticity binder-SMA improved at different temperatures. Under the influence of steel fiber, increasing the degree of shot blasting effectively enhanced the overall shear strength. With more shot blasting, the coverage of steel shot on the specimen's surface gradually increased, the depth of sanding continued to grow, the height of the steel fiber protrusions increased, and the peak of the specimen profile became larger, while the surface depth of the non-steel fiber portion tended to be homogeneous. The correlation of the ETD with Ra, Rq, EMPD, and RMS was better, and the correlation with EMTD and CMT was average. The damage in LUHPC-SMA composite specimens primarily occurred in different surface layers of the bond layer, with no damage to the mixture. he correlation of the shear strength at 25 ℃ with Rq and RMS was good, with an R2 greater than 0.85. The multivariate analysis of shear strength and macro-micro texture parameters showed that for bivariate macro texture parameters ETD, EMPD, EMTD, Ra, Rq, the R2 was greater than 0.85 at 25 ℃, and ranged from 0.6 to 0.85 at -10 ℃. When the bivariate consisted of micro texture parameters RMS and CMT, the correlation for both 25 ℃ and -10 ℃ was better, with an R2 greater than 0.85. The correlation between shear strength and macro-micro texture parameters improved as the number of variables increased.ConclusionsIn view of the influence of steel fibres on the surface texture of the specimens after shot blasting, EMTD and EMPD were used to replace MTD and MPD to characterize the macroscopic texture properties of the materials more effectively; Based on the measurement principle of the sand laying method, the extended tectonic depth (ETD) was proposed as a new evaluation index. Multivariate linear regression analyses of ETD with macro texture parameters (Ra, Rq, EMTD, EMPD) and micro texture parameters (CMT, RMS) were carried out, and the results showed that the correlation between ETD and macro-micro texture parameters was strong. According to the comprehensive consideration of each index parameter under different degrees of shot blasting, it was stipulated that the ETD of the extended construction depth of the lightweight UHPC surface in the interval of 0.60-0.70 mm was considered as a light shot blasting effect, the interval of 0.70-0.85 mm was considered as a moderate shot blasting effect, and the interval of 0.85-1.15 mm was considered as a heavy shot blasting effect. The correlation analysis of the shear strength of the composite specimens at -10℃ and 25 ℃ with the macroscopic texture parameters (ETD, EMPD, EMTD, Ra, Rq) and the microscopic texture parameters (CMT and RMS) showed that: The larger the depth of the extended structure, the better the shear performance at the same temperature; The correlation with the shear strength was gradually strengthened with the increase of the number of variables; and the correlation of the all-variable indexes and shear strength was the best at 0.999. The correlation between all variables and shear strength reached 0.999. Comparing the experimental results under different levels of shot blasting, it was concluded that the extended structural depth of lightweight UHPC surfaces had a positive correlation with the shear strength, and therefore the extended structural depth of ETD was recommended to be 0.85-1.15 mm in this paper.

Extended AbstarctIntroductionIn recent years, China's tunnel engineering has developed rapidly, and concrete lining support technology has been widely used in tunnels, underground engineering projects and deep foundation pits. However, with increasing buried depth and ground stress, ordinary concrete lining support technology often has certain limitations. It is easy to crack during service and shows obvious brittleness when destroyed, which poses a threat to the safety of tunnel engineering. Therefore, in order to prevent cracking, steel fibers with random distribution are usually mixed into concrete to achieve, and in the engineering practice of tunnel lining detection, engineers urgently seek to use high-precision non-destructive testing methods to detect the health status of concrete lining. Therefore, two non-destructive testing methods, Digital image correlation technology (DIC) and Ultrasonic technology (UT), are used to characterize the cracking damage process of concrete, and the strong correlation and complementarity of DIC and UT are verified based on the law of energy evolution.MethodsThe specimens were designed with steel fiber and silica fume content as the control variables, and a total of 9 groups of orthogonal mix specimens were designed for splitting mechanical tests, with a water-glue ratio of 0.43, a mass steel fiber content of 40, 45 kg/m3, and 50 kg/m3, and the mineral admixture silica fume replaced cement with the same amount according to different volume parameters (3%, 6%, 9%), and the dimensions of the 10 groups of specimens in this experiment were: 100 mm × 100 mm × 100 mm.In accordance with CECS13-2009 Fiber Concrete TestMethodStandard, the electro-hydraulic servo pressure testing machine (WAW-1000) is used in the splitting test, the maximum test load is 1000 kN for the control parameters, the stress control loading speed is 0.04 MPa/s, and the failure standard is set to 30% of the peak load. Place the steel gasket up and down at the centerline position of the specimen, and the size of the gasket is 200 mm × 5 mm × 5 mm.Results and discussionIn this paper, by using DIC and UT, based on the energy evolution law, the crack propagation process of SFRC lining under different mix ratios is verified, and the strong correlation and complementarity between DIC and UT test results are verified. The influence of steel fiber and silica fume on fracture mechanical properties is revealed. The main conclusions are as follows:The peak stress at 40, 45 kg/m3 and 50 kg/m3 was increased by 52.73%,81.82% and 73.03% respectively compared with DZ, respectively, that is, the cleavage strength increased significantly when the steel fiber content was 45 kg/m3, and StF45-SF6% showed good safety reserve and ductility, and the increase of silica fume volume content at 50 kg/m3 led to a significant increase in the slope behind the peak of the stress-strain curve, which was negatively correlated with the cleavage strength.According to the cloud map analysis of DIC, it is found that the cracking resistance of steel fiber on the main crack begins to increase after the stress reaches the 90%PMax, and the crack mainly extends longitudinally. When the stress drops below 70%PMax, the main fracture begins to expand laterally, and the inhibition effect of steel fiber across the fracture path gradually decreases to form macroscopic cracks. Under the same steel fiber content, the silica fume volume content was inversely proportional to the CTODc, that is, silica fume could provide additional viscosity and had a good hindrance effect on the expansion of CTOD.According to the acoustic characteristics such as waveform, first wave amplitude and wave velocity, it can be divided into: no damage period, microcrack propagation period, macroscopic crack propagation period, and damage stability period. Based on the principle of energy evolution, it is verified that DIC and UT have strong correlation and complementarity, and the energy storage level of SFRC Kd increased by 12.5%~52.5% compared with DZ, and steel fiber significantly reduced the release rate of elastic strain energy.ConclusionsThe main summary of this paper is as follows: SFRC has a strong post-cracking bearing capacity, with steel fiber content of 45 kg/m3 and silica fume content of 6%, the highest energy storage level and the splitting strength can be increased by 81.82%; Based on the cloud map analysis of DIC, the bridging effect of silica fume is mainly manifested before the 90% peak stress. After 90% peak stress, the crack resistance of steel fibers is gradually enhanced, and the cracks are mainly propagated by longitudinal microcracks. After the stress drops to 70% of the peak stress, the steel fiber crack resistance is gradually weakened, and the fracture begins to expand horizontally rapidly. In addition, the ultrasonic velocity of SFRC showed a trapezoidal hierarchical attenuation trend during splitting damage. Analysis based on the energy evolution law, UT and DIC have strong correlation and complementarity in characterizing the crack propagation process.

IntroductionThe brick-carved cultural relics is a precious cultural resource. The uniqueness of brick carving causes a high requirement for the technique and materials of in-situ repair. The difficulty is to preserve the original features of brick carving while restoring its microstructure. The inorganic reinforcing agents are beneficial for maintaining the physical properties of the historical material and have been considered the optimal choice for restoring the cohesive strength of the historical material in recent years. The restoration material prepared by basic magnesium sulfate cement (BMSC) has the advantages of high tensile strength, high resistance to weather, high viscosity, early strength, and low cost. It has a good effect in reinforcing the weathered sandstone of the cultural relics. The hydraulic lime is widely used due to its waterproof and breathable properties. But it is very expensive. The Silicon-based repair material has good permeability. But it has poor stability in the environment with the changing humidity. Three types of strengthening agents are selected as the alternative options for the restoration of brick carving based on the need for the brick repair and in-situ protection of the ancient mortar during the process of the restoration of brick carving.MethodsThree strengthening agents are Ca-based hydraulic lime, Si-based silica sol, and Mg-based BMSC. Three steps are implemented in order to select the most effective strengthening agent in the restoration of the cultural relics of brick carving. That is the preparation and research of performances of three kinds of imitation bricks, infiltration reinforcement of the ancient material, and the verification of practical engineering. The powder of green bricks is used as the main material for replica bricks. The hydraulic lime, silica sol, and BMSC-based reinforcing agent are firstly mixed with the powder of green brick to form replica bricks, which are the Ca-bricks, Si-bricks and Mg-bricks. The multiple experiments were conducted to investigate the compatibility of replica bricks. The studied properties include the composition of crystal phase, compressive strength, porosity characteristics, and the hydraulic performance of the replica bricks, and so on. WW/T 0065—2015 “Code for Investigation of Stone Cultural Relics Protection Engineering” is referenced. Secondly, the adhesive properties and infiltration reinforcement of the strengthening agents were taken into consideration to evaluate the feasibility of application of these material to the restoration of the brick-carving cultural relics. Finally, the verification of the referred BMSC-based strengthening agent used in actual engineering was conducted because the laboratory environment is different from the complex environment where the cultural relics are located.Results and discussionCa-based and Si-based reinforcing agents only serve to adhere the powder of green brick. The BMSC-based reinforcement agent continues to hydrate after being added to the powder of green brick to form the replica bricks. The main hydration product is the 5·1·7 strength phase. So the BMSC-based reinforcing agent has the strongest adhesion among three types of reinforcing agents. The Mg-brick has the best performance among three kinds of replica bricks, which is similar to the green brick. But Mg-brick has the slight hydrophobicity. The properties of Ca-bricks and Si-bricks are close to the ancient bricks. The bending strength of the masonry of bonded Mg-bricks is 10 times that of the Si-bricks. Only the BMSC-based strengthening agent has no carbonization and has good aging resistance. The infiltration solution with a content of 30% BMSC-based reinforcement agent and a moisture content of 44%-50% has the best effect of reinforcement, maintaining the original physical properties of brick-carved cultural relics while restoring the original cohesion. The referred BMSC - based reinforcing agent can penetrate and bond the slag of brick carving of 9.5 times the mass of agent.ConclusionsThe BMSC-based reinforcing agent demonstrates higher penetration enhancement ability than reinforcing agents based on hydraulic lime or silica sol. The volume stability of the referred BMSC-based strengthening agent meets the requirements. It also can be found that the repair effect of the referred BMSC-based strengthening agent is good after two years. In summary, the optimal ratio of BMSC - based reinforcing agent shows good repair effect at low cost. The Mg-brick and BMSC - based reinforcing agent can be used for the restoration of brick carving.

IntroductionResearch and development of alternative technologies to conventional reinforcement and exploration of printable building materials with excellent properties ECC prepared from polymer fibers has high ductility, excellent toughness, and superior strain-hardening energy dissipation properties. The effects of polyethylene (PE) fiber dosage (1.0%, 1.5%, and 2.0%, in volume) and length (6, 9 mm, and 12 mm) on the pre-strain-hardening early properties, post-strain-hardening mechanical properties, and microstructure of 3D-printed HS-ECC were investigated. This study provides new ideas for the design and performance optimization of 3D-printed HS-ECC, which further promotes the application of 3D-printed technology in construction.MethodsIn this study, we experimentally investigated the effect patterns of polyethylene (PE) fiber doping (1.0%, 1.5%, 2.0%) and length (6, 9, 12 mm) on the pre-hardening early properties, post-hardening mechanical properties, and microstructure of 3D-printed HS-ECC. The rheological properties and early mechanical properties were correlated by actual printing tests. The influence mechanism of mechanical virtual was explored by utilizing microscopic testing means SEM, NMR methods combined with experimental results.Results and discussionThe static and dynamic yield stresses of HS-ECC increased with increasing fiber doping and length, and the effect of fiber doping was more pronounced. With the increase in vertical strain, the stress of the specimens increased approximately linearly before yielding, and the increase in stress slowed down after yielding. Specifically, increasing fiber doping and fiber length increased the early strength of 33D-printed HS-ECC, and the bridging effect of fibers increased with increasing doping and length. The pattern of printable properties was consistent with the rheological properties and early mechanical strength by actual printing tests.The post-hardening mechanical properties of the 3D-printed HS-ECC with 2.0% 12 mm PE fibers yielded a tensile strain capacity of more than 4%, an average crack width of 89.72 m, and a compressive strength of more than 80 MPa. The degree of destruction of the PE fibers after detachment from the substrate increased with fiber doping and length. The 6 mm PE fibers were easier to pull out than 12 mm, and thus the ductility of the material increased with the increase in fiber doping and length. to pull out and thus the ductility of the material decreases. In addition, nozzle extrusion-based 3D-printed HS-ECC allows for effective directional fiber orientation, resulting in increased ductility of the 3D-printed HS-ECC.The pore size distributions peaked in the range of 0.001 μm to 0.010 μm. Cast samples contained and the proportion of small pores in the casting samples is less than 90%, while the 3D-printed samples are 60% to 70%, which indicates that the 3D printed samples contain a higher number of large pores. The primary and secondary peaks of samples V1, V2, L1, and L2 are lower compared to those of samples V3 and L3, and the trend suggests that the increase of fibers raises the number of pores, which results in the decrease of compressive strength. Although the variation of the primary peaks of the 3D printed samples is consistent with the pouring trend, the pattern of the secondary peaks is complex, which may be related to the time between the printed layers and the pressure on the upper layer of the material, resulting in an irregular distribution of pores. The total porosity increases by about 21.75% and 11.75% with increasing fiber doping and fiber length, while the mechanical properties of 3D-printed HS-ECC specimens decrease at the same time. The comparative results show that the porosity of cast HS-ECC is 1.24 to 1.67 times higher than that of 3D-printed HS-ECC, but the harmful porosity of 3D-printed HS-ECC accounts for about 30%, which may lead to the decrease in the mechanical properties of large-scale components.ConclusionsWith the increase of fiber doping and fiber length, its dynamic and static yield stress increases. In addition, the early mechanical strength of 3D-printed HS-ECC increases. Through the actual printing test, the pattern of its printable properties is consistent with the rheological properties and early mechanical strength. The post-hardening mechanical property test results yielded that the 3D-printed HS-ECC containing 2.0% 12 mm PE fibers possessed a tensile strain capacity of more than 4%, an average crack width of 89.72 m, and a compressive strength of more than 80 MPa. The degree of damage of PE fibers after separation from the matrix increased with fiber doping and length. 6 mm PE fibers were easier to pull out compared to 12 mm, resulting in a decrease in the ductility of the material. In addition, nozzle extrusion-based 3D-printed HS-ECC allows for effective directional fiber orientation, resulting in an increase in the ductility of 3D-printed HS-ECC. The increase in fiber doping and length increased the total porosity by 21.75% and 11.75%, respectively, which led to a decrease in the mechanical properties of 3D-printed HS-ECC specimens. 3D-printed HS-ECC showed a decrease in the intra-strip porosity compared to casting, and an increase in the interlayer and inter-strip porosity resulted in a decrease in strength.

IntroductionPolycarboxylate superplasticizer (PCE) is commonly used in cement-based materials, which has the advantages of low dosage, high water reduction and strong molecular designability, which has been widely concerned by many researchers. PCE adsorbs on the surface of cement particles, and then breaks the cement flocculation structure, playing the effect of dispersing cement particles. However, it is known to all that the capacities of dispersing and dispersing retention of PCE to cement slurry are influenced by many parameters, such as cement components and mixing conditions. The polymer adsorption was shown to be very sensitive to the concentration of divalent ions like sulfate ions, so the sulfate ions of the cement slurry appear to be one of the most important parameters that adversely affect performances. In addition, the molecular structure parameters of PCE have an important influence on the adsorption behavior. Therefore, molecular structure parameters are important factors affecting PCE sensitivity to sulfate.Although previous studies have found that PCE with ionizable side chains (ISC-PCE) has better dispersion retention than PCE with nonionizable side chains (NSC-PCE), the effect of changes in side chain ionizability on its sensitivity to sulfate (sulfate tolerance) is unclear. Therefore, to more effectively realize the performance control of PCE on cement-based materials, the influence of side chain ionizability on sulfate tolerance of PCE is needed. Based on the previously reported ISC-PCE and NSC-PCE, the sulfate concentration was controlled by adding sodium sulfate, under which the new mixed cement slurry flow and its retention and rheological properties were tested to assess the dispersion. The size of PCE in solution, the amount of adsorbed polymer and zeta potential were combined to assess PCE tolerance to SO42-. The salt added species were changed and the effects of SO42- competitive adsorption and ion concentration on PCE performance were analyzed by rheology. The results can help to understand the effect of PCE on cement dispersion in the presence of ion competition and provide a new direction for opening up new structural PCE with good compatibility.MethodsThe fluidities of cement slurries were measured according to the Chinese standard GB/T 8077—2012. A RST-SST rotational rheometer with a paddle rotator of VT40-20 was used (shear rate: 10 s-1→50 s-1→10 s-1). The data was processed with Rheology 3000 software to obtain the yield stress. The hydrodynamic radii (Rh) of the polymers were determined in saline conditions by dynamic light scattering experiments. The adsorbed capacities of the PCEs on cement surfaces, which were calculated from the difference in the concentration of polymers, were measured on a Vario Total Organic Carbon (TOC) analyzer by testing the PCE adsorption after different adsorption times. The zeta potentials of the cement pastes were measured at 25 ℃ on a Malvern Zetasizer Nano ZS90 analyzer. The MD simulations used the Gromacs-4.6.7 software package and a conventional oplsaa force field with RESP charges. The UFF force field was used for the substrate. The equilibrium MD simulation was conducted under the NPT ensemble for a total run time of 20 ns at a relaxed liquid configuration (25 ℃). The solution environment simulations were performed using 3000 water molecules. A relaxation system was selected and the energy was minimized by the steepest descent method with a termination gradient of 100 kJ/(mol&#x00B7;nm) before the relaxation. The system temperature is maintained constant through a Nos-Hoover thermostat, and periodic boundary conditions were applied to all three dimensions. Long-range electrostatics within a relative tolerance of 1×10-6 is calculated by the particle mesh Ewald method and a cut-off distance of 1 nm was used as the Ewald interaction and van der Waals interactions. The bond lengths of hydrogen atoms were constrained by the LINCS algorithm. A leap-frog algorithm was used with a time step of 1 fs.Results and discussionCompared with no salt, the hydrodynamic radius of NSC-PCE and ISC-PCE decreased by 36.9% (to 8.40 nm) and 8.1% (to 15.98 nm), the cement slurry mobility decreased by 21.7% and 4.3%, the adsorption volume decreased by 21.7% and 3.9%, and the yield stress increased by 42.7% and 27.8%, respectively.ConclusionsThe main conclusions of this paper are summarized as following. The improved side chain ionizability of PCE can significantly improve the dispersion stability and sulfate tolerance, and reduce its sensitivity to sulfate competitive adsorption and ionic strength. Based on the above results, sulfate tolerance of both PCE was quantitatively assessed (the sulfate resistance index of ISC-PCE was increased by 32% as compared to that of NSC-PCE) and verified by all-atom molecular dynamics simulations. The present results not only deepen the understanding of the impact of sulfate on PCE performance, but also provide a new direction for the development of new PCE with good compatibility.

IntroductionIn marine environments, the conventional steel reinforcement is prone to corrosion, leading to severe damage to concrete. Additionally, the deficiencies of ordinary concrete in terms of resistance to marine corrosion and impermeability significantly shorten the service life of marine concrete structures, which has attracted widespread attention. To enhance the durability of marine concrete, researchers are actively exploring new solutions. Among these, the use of FRP (Fiber Reinforced Polymer) reinforcement to replace traditional steel bars effectively addresses the issue of steel corrosion. Calcium sulfoaluminate (CSA) cement concrete, with its characteristics of early strength, high strength, corrosion resistance, and excellent impermeability, is particularly suitable for marine concrete structures that require high early-strength and durability. Based on this, the present study investigates the specific impact of different bond lengths of GFRP (Glass Fiber Reinforced Polymer) and BFRP (Basalt Fiber Reinforced Polymer) reinforcement on the bonding performance of the FRP-CSA full-coral aggregate concrete system.MethodsThis study investigated the influence of different bond lengths of FRP bars in full coral aggregate seawater sea-sand sulphoaluminate cement concrete (FCASS-CSAC) on the bond properties. This study used two different types of bars (GFRP and BFRP) and three different bond lengths (5 d, 7.5 d, 10 d, where d represents the diameter of the bars) to cross combine into 6 different types of specimens. All specimens were demolded after 24 h treatment and cured for 28 d in a standard curing chamber (temperature of (20±2) ℃, relative humidity of 95%). Subsequently, compressive strength tests and central pull-out tests were conducted to investigate the bond performance between FCASS-CSAC and FRP bars.Results and discussionWhen the bond length of BFRP and GFRP reinforcement bars is 5 d, the bond stress is generally higher than when the bond length is 7.5 d or 10 d. Specifically, for BFRP bars, the bond strength at a bond length of 5 d is approximately 30% and 60% higher than that at bond lengths of 7.5 d and 10 d, respectively. The bonding performance of BFRP and GFRP reinforcement bars was compared, and the results show that, in the absence of ribbed features, BFRP reinforcement typically exhibits superior bonding performance, with the bond strength generally about 40% higher than that of GFRP bars. This suggests that BFRP reinforcement has a potential advantage in providing stronger bond strength, which may be related to its material properties and the way it interacts with the matrix.ConclusionsThe main conclusions of this study are summarized as follows. The bonding performance of BFRP reinforcement with FCASS-CSAC is generally superior to that of GFRP reinforcement, with an overall bond strength about 40% higher. The bond strength of both types of reinforcement decreases as the bond length increases, with BFRP reinforcement showing a significantly higher bond strength at a bond length of 5 d compared to 7.5 d and 10 d. Based on the experimental results, an empirical formula for predicting bond strength was proposed. Furthermore, finite element simulation analysis was conducted, and the analysis results showed good agreement with the experimental findings.

IntroductionIn-situ polymerized cementitious materials (iPMCM) exhibit exceptional fluidity, interfacial adhesion, and toughness, making them promising candidates for rapid repair engineering and 3D printing applications. However, the delayed cement hydration caused by polymer significantly impedes early strength development, limiting their practical applications. Nano-silica (NS) has been proven to considerably enhance the early-age mechanical properties of cementitious materials due to its filler effect, nucleation effect, and pozzolanic effect, offering a solution for improving the strength development of iPMCM at the early age. However, the synergistic effects of NS and in-situ polymerization on the mechanical development remain unclear. This study systematically investigates the interaction of NS and in-situ polymerization on the hydration kinetics, microstructure, and mechanical properties of iPMCM. And the enhancement mechanism of NS on both the cement microstructure and the polymer network was in-depth discussed. The findings from this study provide an effective strategy for improving the early-age mechanical properties of iPMCM, broadening their real-world applications.MethodsOrthogonal experiments L25 (56) were designed to optimize acrylamide (AM) monomer (1%-5% of cement mass), potassium persulfate (KPS) initiator (1%-5% of monomer mass), and NS (0-0.4% of cement mass) dosages based on 6 h compressive strength. P.I 42.5 cement, AM, KPS, and 15 nm NS were used with a fixed water-to-cement ratio of 0.4. NS was pre-dried at 60 ℃ for 24 h before dispersing in water with AM and KPS, and then the resulting solution was mixed with cement to prepare pastes. Samples were cast into 40 mm × 40 mm × 40 mm molds. After demolding curing for 1 d, the samples were cured at 20 ℃ and 95% RH for specific curing ages prior to mechanical property measurement. The hydration kinetic of cement pastes was monitored by a TAM Air calorimeter. The hydration products of hardened cement pastes were characterized by XRD and TGA. SEM and MIP were employed to observe the microstructure and to analyze the pore structure of iPMCM at different ages, respectivelyResults and DiscussionThe orthogonal experiment identified 4% AM, 0.3% NS, and 4% KPS as the optimal formulation, achieving a 284% increase in 6 h compressive strength (from 1.38 MPa to 5.3 MPa) and 381% increase in 6 h flexural strength (form 0.36 MPa to 1.73 MPa) compared to the control group. In addition, the optimal group exhibited varying degrees of improvement in compressive and flexural strengths than the control and in-situ polymerization groups after curing for 7 d and 28 d. The evolution of heat flow analyses during the cement hydration indicates that NS reduced the nucleation barrier for C-S-H formation and thus advancing silicate hydration. It resulted in an increase of CH content by 17.8%. Concurrently, NS promoted the earlier AM polymerization releasing a more significant heat, which contributed to accelerating cement hydration, and thereby improving the early-age compressive strength. MIP results suggest that the incorporation of NS into iPMCM reduced harmful pore (>50 nm) volume by 71.1% and increased less-harmful pore (20-50 nm) content, compared to the control group, significantly refining the pore structure of the hardened cement pastes. SEM observations demonstrate a denser organic-inorganic network in NS modified PAM hydrogel where NS is likely to act as a physical crosslinker via hydrogen bonding with polyacrylamide strengthening the polymer network.ConclusionsThis study demonstrates that modification using nano-silica effectively enhances the early strength of iPMCM with the optimal formulation of 4% AM, 0.3% NS, 4% KPS, which achieved a 284% improvement in 6 h compressive strength while maintaining superior 28 d flexural strength. The comprehensive experiment analyses conclude that the roles of NS in the early-age mechanical development of iPMCM includes: (i) Improving cement hydration and microstructure. Owing to its nucleation effect, NS accelerates the silicate hydration compensating for the delaying effect of in-situ polymerization on cement hydration. And the presence of NS refines the pore structure of iPMCM by reducing the amount of harmful pores, thus further improving the early strength of iPMCM. (ii) Strengthening the polymerization network. NS advances the occurrence of polymerization with a significant heat released. In iPMCM, NS may interact with polyacrylamide via hydrogen bonding, as a physical crosslinker strengthening the polymer network. These further contribute to the early-age strength development of iPMCM. The findings from this study provide a scientific foundation for the applications of iPMCM in rapid repair engineering, 3D printing structures, etc. The long-term durability and scalability for industrial applications will be further explored in future studies.

IntroductionThe alkaline nature of cementitious materials has high potential of carbon sequestration. Research has shown that carbonation curing to cementitious materials at early age can improve their strength and densify their microstructure. Consequently, it is expected that carbonation curing can enhance the durability of concrete structure. However, carbonation can naturalize the alkaline environment of concrete, raising risks of steel corrosion. The debate between the carbonation-induced microstructure improvement and the neutralization-raised corrosion risks has not been resolved yet. Therefore, it provides great incentives to understand if carbonation of cementitious materials at early age accelerates corrosion of steel bar or not.MethodsA hybrid calcium-sulphoaluminate and Portland cement (CSA-PC) mortar was prepared to coat steel bars of 0.7 mm. Three carbonation durations of 4, 24 h and 72 h were designed to treat the CSA-PC mortar. The alkalinity of the composite mortar after carbonation was characterized by phenolphthalein chromatography, and the water sorptivity of non-carbonated and carbonated mortar specimens was measured by using a contrast-enhancing X-ray computed tomography (XCT). The corrosion process of the steel bars was measured by open-circuit potential and corrosion current density up to 40 chlorine-salt drying-wetting (CSDW) cycles. The microstructure of the mortar and the corrosion rust distribution of the steel bars after the CSDW action were characterized by BSE-EDS and image analysis.Results and discussionEarly-age carbonation significantly reduced the alkalinity of the mortar matrix, which recovered after standard curing up to 28 d but remained below the alkalinity threshold for the formation of passivation of steel (pH=11.5). Carbonation densified the pore structure of the hybrid cement mortar and reduced the capillary water absorption. The water sorptivity of the carbonated mortar specimens was significantly lower than that of the uncarbonated specimens as observed by XCT, indicating an improvement in the impermeability of the mortar matrix. After 10 CSDW cycles, the open circuit potential of the carbonated specimens decreased significantly and the corrosion current density increased by nearly one order of magnitude. The early-age carbonation significantly increased the probability and rate of corrosion of the steel bars in the mortar under cyclic CSDW actions. BSE-EDS analysis further showed that after carbonation, the rebars were severely corroded with corrosion pits up to 200 μm in depth and 20% in area; corrosion products migrated and filled the mortar matrix around the rebars, generating cracks.ConclusionsThe alkalinity of the mortar matrix decreased after early age carbonation, following recovery to a certain value after standard curing, which remained below the alkalinity threshold for steel passivation. Carbonation was able to improve the compactness of the mortar matrix and enhance the material's impermeability. The open circuit potential of the carbonated material was lower and the corrosion current density was one order of magnitude higher after 10 CSDW cycles. Serious corrosion of the rebar occurred in the mortar after carbonation, the corrosion products migrated to the surrounding mortar matrix, and the volumetric expansion led to cracking of the matrix. The findings suggest that although early age carbonation may help to improve the performance of cementitious material matrix, it may be detrimental to the durability of reinforced concrete.

IntroductionThe precise characterization of microstructure in cement-slag blended pastes is pivotal for understanding reaction mechanisms and optimizing material performance. Traditional methods relying on single-model analysis face limitations in distinguishing phases with similar grey value ranges and integrating multi element mappings. This study proposes an intelligent Backscattered electron and Energy-Dispersive X-ray Spectroscopy (BSE-EDS) image analysis methodology, integrating standardized pre-processing procedures, Potential of Heat-diffusion for Affinity-based Trajectory Embedding and Gaussian Mixture Model (PHATE-GMM) based phase identification model, and Glue-based Multiview visualization, to achieve multimodal characterization of cement-slag pastes. The framework bridges the gap between the BSE image and EDS element mappings with multimodal features in cementitious systems, enabling comprehensive phase identification, element migration analysis, chemical composition analysis, phase evolution tracking, and microstructure quantitative characterization.MethodsCement-slag paste (30% slag replacement ratio, water-to-binder ratio 0.4) were prepared, cured (0, 7 d and 14 d), and examined by Scanning electron microscope (SEM) after epoxy impregnating and polishing. The BSE image, qualitative element mappings, and quantified element mappings were acquired with accelerating voltage of 15 kV, working distance of 11 mm. A BSE-EDS data preprocessing pipeline was developed: (1) Guided filtering enhanced EDS element mapping resolution using BSE image as guided image; (2) Generating phase masks excluding pore and epoxy interference; (3) Super-pixel segmentation on phase region (10 000 units) to integrates grey value information from BSE images and element information from quantified element mappings. The PHATE-GMM model combined PHATE dimensionality reduction algorithm for 2D visualization with GMM for clustering PHATE-derived attributes, achieving automated and interpretable phase identification. Glue platform enabled synchronized multi-view interactive analysis (element scatterplots, phase maps, PHATE plots, element histograms, density plots) to validate phase identification results and explore phase relationships.Results and discussionPHATE-GMM model achieved great consistency with visual inspection-labeled phases. In raw materials, distinct clusters corresponded to cement clinker, slag and gypsum. The C3A/C4AF phases are frequently embedded within the C2S/C3S phases, which results in partial super-pixel regions containing both phases during super-pixel segmentation. Consequently, interconnected clusters can be observed in PHATE plot. For hydrated pastes, rim phases (e.g., C2S/C3S-rim, slag-rim, CH-rim) emerged as transitional zones between critical phases and C-S-H. The spatial distribution and element composition analyses of both slag-rim and slag demonstrate that the slag-rim exhibits a lightly higher Mg/Ca ratio compared to slag, indicating a distinct enrichment of Mg ions in the rim region. Local analysis mode via Glue facilitates element exploration in un-clustered cementitious systems, particularly for complex or novel binders. Global analysis mode via Glue, suitable for well-characterized cementitious systems. PHATE-derived element density maps further enable visualization of ion migration pathways. The phase network topology diagram achieves tri-dimensional synergistic representation through spatial positioning, radial scale, and connection line thickness parameters, while preserving the original relational information between phases shown in PHATE plots and simultaneously incorporating phase content features. The BSE-EDS image intelligent analysis methodology established in this study enables efficient and accurate determination of pore and phase in cement-slag binders, thereby enabling multiple downstream applications including elemental composition analysis of phases, investigation of evolutionary patterns, and quantitative characterization of microstructure.Conclusions1) The proposed pipeline for generating BSE-EDS datasets demonstrates strong generalizability and practicality, effectively mitigating the impact of pore interference and excessive interaction volume on phase identification, providing a viable data management solution for multimodal feature extraction and downstream analysis in cementitious systems.2) The developed PHATE-GMM phase identification model exhibits high interpretability and intelligence, enabling comprehensible automated phase identification. The visualization structure of PHATE plot offers novel analytical insights for scientifically describing reaction mechanisms and microstructure evolution in cementitious systems.3) The Glue-based multimodal feature analysis technique facilitates synchronous and interactive exploration of chemical and spatial modalities, allowing for expert-guided optimization of automated phase clustering results.4) The intelligent BSE-EDS image analysis methodology enables comprehensive downstream applications, which fully exploits the analytical potential of BSE-EDS for microstructural characterization, realizing the technical vision of "single independent micro-characterization - multimodal feature fusion analysis".

Cement concrete materials are one of the most widely used building materials in modern infrastructure, but their production process is associated with high energy consumption and significant carbon emissions, imposing substantial environmental and resource pressures. While traditional mineral admixtures (such as fly ash and slag) can improve concrete workability, enhance mechanical properties, reduce hydration heat, and improve durability by partially replacing cement, they suffer from low early-stage activity. The application of advanced grinding or sorting technologies to refine mineral admixtures into ultrafine particles has proven effective. This process increases the specific surface area of the admixtures, thereby enhancing particle surface energy and reactivity, which compensates for the deficient early-stage activity of conventional mineral admixtures. Ultrafine mineral admixtures demonstrate remarkable potential in improving concrete workability, early-stage mechanical performance, and durability. In recent years, this approach has garnered widespread attention in academic and industrial research.This paper first elucidates the characteristics of fly ash microsphere, ultrafine fly ash, and ultrafine slag powder. Subsequently, it systematically investigates the impacts of these three typical ultrafine mineral admixtures on various properties of cement and concrete, accompanied by comparative analyses of their performance differences compared with conventional mineral admixtures. Furthermore, the intrinsic properties, compatibility design principles, and comprehensive effects of ultrafine composite mineral admixtures on cement concrete performance are expounded. Finally, the current application status of ultrafine mineral admixtures in cement concrete is summarized. Ultrafine mineral admixtures exert multiple beneficial effects in cementitious systems, including filling effect, morphological effect, nucleation effect, pozzolanic effect, density effect, dispersion effect, specific surface area effect, and interfacial effect. Their dosage and fineness significantly influence critical parameters such as water demand for standard cement consistency, setting time, rheological properties, and hydration heat release. Appropriately formulated fly ash microsphere, ultrafine fly ash, or ultrafine slag powder with optimized fineness can enhance concrete workability, improve durability, inhibit shrinkage, and suppress alkali-aggregate reactions, though potentially compromising carbonation resistance. These materials also demonstrate pore structure refinement, microstructural optimization, and mechanical performance enhancement. The primary distinction between ultrafine and conventional mineral admixtures (e.g., fly ash and slag) lies in particle fineness, which yields differential performance outcomes despite sharing identical chemical reaction mechanisms. Conventional admixtures typically enhance concrete workability, long-term strength, and durability at the expense of early-age strength reduction. In contrast, ultrafine variants leverage superior pozzolanic reactivity and filling capability, where the increased specific surface area amplifies nucleation effects, leading to significant improvements in early-age strength development and workability. Their micro-aggregate effect and enhanced pozzolanic activity further contribute to more pronounced durability enhancement. Compared with single-type ultrafine admixtures, ultrafine composite mineral admixtures employ “gradient hydration” and “functional complementarity” mechanisms to synergistically accelerate hydration processes. This strategy effectively increases amorphous C-S-H gel formation, optimizes pore structure of hardened paste, and enhances matrix compactness through multi-scale interactions. In the concrete mix design, the dosage of ultrafine mineral admixtures is recommended to be controlled between 20% and 35%, which can significantly improve the workability and mechanical properties of concrete. However, excessive dosage may trigger a significant dilution effect, which is detrimental to the overall performance of concrete. Ultrafine mineral admixtures have shown great application potential in enhancing the workability of cement-based repair materials, manufacturing cement-based refractory materials, producing high-performance insulation materials, enabling steam-free curing of prefabricated components, and improving the comprehensive performance of ultra-high-performance concrete (UHPC). Currently, the application of ultrafine mineral admixtures mainly faces two major challenges: First, the relevant standard and specification system is still incomplete. Second, it is challenging to produce ultrafine powders that meet the standard requirements using diverse and complex raw materials. Due to the complex sources of mineral admixtures, the performance of ultrafine mineral admixtures can vary significantly, and improper dosage control may adversely affect the performance of concrete. Therefore, it is urgent to improve the standard specifications, enhance the preparation processes and equipment, reduce energy consumption and pollution, and further investigate their effects on the hydration mechanisms of cementitious materials to promote their wider application.Summary and prospectsCompared with traditional mineral admixtures such as fly ash and slag, ultrafine mineral admixtures, characterized by higher specific surface area and pozzolanic reactivity, have shown significant advantages in improving the workability, mechanical properties, and durability of cementitious materials. Against the backdrop of green and low-carbon transformation in the cement and concrete industry, significant progress has been made in the application research of ultrafine mineral admixtures. By reducing the clinker factor and decreasing the cement content per unit of concrete, they provide an effective pathway for achieving sustainable development in building materials. Future research should focus on the following key areas: First, improving existing grinding equipment and processes to achieve rational composite grinding of mineral admixtures, thereby enhancing quality and reducing costs. Second, leveraging artificial intelligence technology to accurately predict the performance of ultrafine mineral admixtures, significantly improving design efficiency. Third, conducting in-depth studies on the hydration synergistic effects and microstructural evolution mechanisms of different ultrafine mineral admixtures. Fourth, refining technical standards and specifications to promote product quality improvement and the expansion of application fields. With technological advancements and increasing environmental demands, ultrafine mineral admixtures will play a more important role in enhancing the performance of cement concrete, reducing costs, and driving the development of green buildings.

As an ultra-wide bandgap semiconductor, diamond stands out with its exceptional properties: Mohs hardness up to 10, thermal conductivity exceeding 2000 W/(m·K), a 5.47 eV bandgap, and chemical inertness. These attributes make diamond indispensable in high-power electronics, optoelectronics, quantum computing, and aerospace engineering. With the rapid growth of diamond synthesis technology, traditional mechanical machining faces insurmountable limitations in achieving sub-micron precision and fabricating complex micro-nano structures. Laser processing, leveraging non-contact ablation, localized energy deposition, and precise parameter control, has emerged as a transformative solution for diamond machining.The mechanism of laser interaction with diamond involves two primary steps. Initially, diamond is transformed into the graphite phase through laser induction. After that, the graphitized layer is removed via vaporization and chemical etching to complete the material processing. Surface graphitization occurs as a result of photon energy exciting the transition of sp3 bonds between carbon atoms to sp2 bonds. This process is influenced and directed to a certain extent by laser parameters and the thermal gradients in the laser - irradiated area. Regarding the mechanism of laser - induced graphite removal, lasers with different pulse widths, ranging from continuous lasers to extremely short femtosecond pulses, behave differently. Laser pulses having pulse width exceeding one picosecond can heat both the lattice and electrons simultaneously. In contrast, laser pulses with a width less than 1 ps mainly excite electrons through nonlinear ionization. Nanosecond or longer - pulse lasers typically cause lattice heating, which can induce solid - solid phase transitions, amorphization, melting, or evaporation. On the other hand, femtosecond lasers remove material through expanding plasma, which helps reduce damage to the remaining surface. Based on these differences, each type of laser has its own set of advantages and limitations in specific applications.Regarding surface treatment and polishing, while laser processing outperforms mechanical methods in efficiency and material loss, its final surface roughness traditionally lagged behind mechanical polishing. Recent advancements in multi-laser source polishing, laser-assisted polishing, and pulse burst mode have demonstrated transformative potential. High-power lasers with pulse burst mode (energy density <5 J/cm2) reduced surface roughness by 50% while maintaining minimal HAZ (<3 m). Furthermore, a hybrid process combining laser trimming and plasma-assisted polishing (PAP) achieved atomic-scale flatness (Ra <10 nm). This method uses laser pretreatment to remove macroscopic defects followed by plasma etching for nanoscale smoothing.In surface treatment and polishing, while laser processing outperforms mechanical methods in efficiency and material loss, its final surface roughness traditionally lags behind conventional mechanical polishing. Recent advancements in multi-laser source polishing, laser-assisted polishing, and pulse burst mode have demonstrated transformative potential. Sequential polishing with hybrid laser sources (e.g., nanosecond + femtosecond lasers) combines ablation effects and defocused beam strategies to reduce peak-valley height differences while maintaining laser energy near the ablation threshold (<5 J/cm2). This approach minimizes thermal damage, ensures optical surface quality, and enables precision material removal. High-power lasers with pulse burst mode achieve 50% roughness reduction (e.g., from 0.41 m to 0.2 m Sa) through energy density optimization (<5 J/cm2), resulting in minimal heat-affected zones (<3 m). Additionally, a hybrid process integrating laser trimming and plasma-assisted polishing (PAP) achieves atomic-scale flatness (Ra <10 nm). This method uses laser pretreatment to eliminate macroscopic defects followed by plasma etching for nanoscale smoothing.Summary and prospectsLaser processing has demonstrated transformative potential in diamond machining. However, current technologies face several challenges. Laser polishing of diamond requires further roughness reduction, with sequential multi-laser polishing, pulse burst mode processing, and laser-assisted polishing representing viable next steps. Mitigating thermal damage from long-pulse lasers and improving efficiency of short-pulse lasers are critical for widespread adoption. Future research should integrate short- and long-pulse laser advantages through process design or source selection to achieve high-precision, high-quality, and low-defect machining. In recent years, innovative technologies such as Bessel beam shaping, femtosecond laser direct writing, and laser microjet have further broken through the limitations of traditional processes, providing brand new solutions for the manufacturing of quantum devices, optical components, and high-precision microstructures. In conclusion, while challenges persist, continuous advancements in laser technology promise to address these bottlenecks, enabling scalable diamond machining for next-generation applications.

High-entropy materials (HEMs) tend to be composed of five or more elements or have a configurational entropy greater than 1.5R (R is gas constant). The high configurational entropy caused by the complex elements can enhance the solubility of elements within the structure and promote the formation of a single-phase structure. The differences in electronegativity and ionic radii among the constituent elements introduce lattice distortion and sluggish-diffusion effect, playing a critical role in regulating the physical and chemical properties and micromorphology of HEMs. Due to these advantages, the high-entropy strategy has emerged as an effective approach for advancing the existing materials and developing novel ones. Thus, the diversity of HEMs has expanded from high-entropy alloys and intermetallic compounds to high-entropy oxides, sulfides, carbides, and so on. Consequently, their application fields are wide and show great potential in electrochemical energy storage fields.The development of high-performance solid-state electrolytes (SSEs) is essential for advancing solid-state batteries to satisfy the increasing demands for high energy density, enhanced safety, and long-term stability. As key components, SSEs play an indispensable role in providing migration pathways for alkali metal ions, making the facilitation of ion transport to achieve high ionic conductivity a primary objective in their development. Among various SSEs, inorganic ones have emerged as prominent candidates due to their relatively high ionic conductivity and stability. However, current inorganic SSEs require further improvements in ionic conductivity and overall performance to meet practical application requirements. A particularly important factor influencing the performance of inorganic SSEs is their local structural configuration. The arrangement of ions and the degree of structural order directly govern the migration energy barrier, which in turn has a great influence on ionic conductivity. Tailoring the local structure through compositional engineering and structural modulation offers a promising pathway to minimize migration energy barriers, thereby enhancing ion transport efficiency.Given the advantages of the high-entropy strategy in regulating local structures, this approach has been preliminarily applied to optimize the performance of inorganic SSEs, including oxide, sulfide, and halide SSEs. The mechanisms by which high-entropy strategies improve properties vary depending on the intrinsic characteristics of each prototype structure. For oxide SSEs, the incorporation of multiple elements effectively regulates site energy and refines the local structure of ion migration pathways, facilitating ion transport. In contrast, sulfide and halide SSEs benefit from their high anion tolerance, which enables the introduction of diverse anion species. This diversity disrupts the arrangement of adjacent Li+ and directly modulates ion migration behavior, contributing to improved ionic conductivity. This work systematically reviews the unique characteristics and performance enhancement mechanisms of high-entropy oxide, sulfide, and halide SSEs. Furthermore, it identifies key challenges and proposes future research directions aimed at advancing the design and improvement of high-entropy SSEs, paving the way for their application into next-generation solid-state batteries.Summary and prospectsThe high-entropy strategy is an effective approach for optimizing and developing SSEs. It can not only adjust the configurational entropy to stabilize the structure, but also enhance the ionic conductivity of SSEs by regulating site energy, structural disorder, and the distribution of mobile ions. For high-entropy oxide SSEs, cation substitution is primarily employed to regulate site energy and local structure, thereby improving ion transport properties. In high-entropy sulfide and halide SSEs, the anionic sublattice offers greater flexibility in composition. Hence, beyond cationic site regulation, modifications to the anionic sublattice result in a more pronounced effect on ionic conductivity. Furthermore, such strategies can regulate micromorphology, air stability, and resistance to oxidation and reduction, laying a solid foundation for high-energy-density and high-safety solid-state batteries.However, high-entropy solid-state electrolytes remain in their infancy, and their development faces several critical challenges and key issues. First, in the design of high-entropy solid-state electrolyte materials, the selection of elements critically governs the properties, while the compositional complexity poses significant challenges in establishing universal design principles. Besides, the development of high-entropy solid-state electrolyte materials necessitates careful trade-offs among different properties. A key scientific challenge lies in rationally choosing elements that simultaneously modulate structural configurations to enhance ionic conductivity while maintaining air stability and electrochemical stability. Current research has paid insufficient attention to elemental cost-effectiveness and safety implications, both of which substantially impact the practical application potential of these materials. Further investigations should prioritize the adoption of low-cost and high-safety raw materials to enhance the practical application. Second, current research on high-entropy SSEs mainly focused on the ionic transport properties. However, achieving practical applications requires a deeper investigation into their interfacial compatibility and stability with high-voltage cathodes and lithium metal anodes, which are critical for the performance of full battery systems. Third, future research could introduce machine learning methods to predict and screen elemental combinations and structural designs, thus accelerating the development of high-performance solid-state electrolytes. However, high-entropy solid-state electrolytes remain in the early exploratory stage, where limited experimental data and unclear structure-properties relationships constrain the accuracy of the data-driven model. To address this, researchers could combine conventional elemental doping strategies with quantitative analyses of individual element contributions to material performance. Concurrently, theoretical calculations could generate supplementary theoretical datasets. Furthermore, experimental validation should be employed to refine predictive models, establishing a “computation-data-experiment” collaborative framework. This approach will improve the model's reliability and generalizability, ultimately accelerating the rational design of high-entropy solid-state electrolytes.Although research on high-entropy SSEs is still in its early stages, these materials are expected to provide new avenues for advancing the practical applications of solid-state batteries through ongoing fundamental studies and technological innovations.