Adding calcium silicate hydrate seed-polycarboxylate ether (C-S-Hs-PCE) to cement-based materials can effectively improve the early strength. C-S-Hs-PCE can provide nucleation sites for the formation of a hydration product C-S-H gel, effectively promoting the generation of the C-S-H gel, and accelerating the process of cement hydration. The acid-ether ratio is an important structural parameter of comb-type PCE molecules, having an impact on the synthesis and early strength enhancement of C-S-Hs-PCE. This paper investigated the effect of acid-ether ratio on the particle size of C-S-Hs-PCE and the early strength of cement-based materials by using dynamic light scattering (DLS) particle size analysis, total organic carbon analysis, X-ray diffraction, low-field time-domain nuclear magnetic resonance, scanning electronic microscopy, isothermal calorimetry, and compressive strength tests, respectively. The results show that the C-S-Hs-PCE formed at a high acid-ether ratio PCE has a smaller particle size, which is more conducive to promoting the hydration of the silicate phase and the generation of calcium hydroxide and C-S-H gel, thereby accelerating the hydration of the paste, reducing the total porosity of mortar, and improving the early compressive strength of mortar, especially within 24 h.

It is essential for the adhesion mechanism of the cement-asphalt interface to evaluate the performance of cement-asphalt composite material in a micro-scale. The interface molding experiment was designed in laboratory according to the actual formation process. The influences of environmental temperature, grouting type and asphalt type on the cement-asphalt interfacial bonding characteristics were investigated. The microstructures and features of the cement-asphalt interfacial transition zone were analyzed by scanning electronic microscopy, energy dispersive spectroscopy, and Fourier transformed infrared spectroscopy. The hydrophilia of grouting and asphalt was evaluated by contact angle analysis. The adhesion mechanism of the cement-asphalt interface was investigated. The results show that the bonding strength of the cement-asphalt interface decreases with increasing the temperature. The interfacial bonding strength of sulphoaluminate cement-asphalt is 1.03-1.98 N/mm2 at 25-35 ℃, which is more than 10% greater than that of the Portland cement-asphalt. The interfacial bonding strength of sulphoaluminate cement-asphalt is 0.32-0.38 N/mm2 at 60 ℃, which is increased by >80%, compared with that of Portland cement-asphalt. Grouting has a slight emulsification effect on the asphalt interface region, reflecting that the more free asphalt changes to structural asphalt and increases the bond strength. The cement-asphalt interfacial adhesion is due to the physical force. The adhesion failure is the damage between the structural asphalt and free asphalts. Based on the adhesion mechanism, the asphalt-cement composite material can be improved to reduce the crack risk of cement grouting asphalt composite pavement.

It is important for the further improvement of lithium-ion battery energy densities to develop high-specific-capacity cathode materials. Li3V2O5 has attracted much attention due to its high specific capacity, even exceeding 240 mA?偸h/g. However, its low electrochemical cycling stability induced by the low Li+ transport dynamics and irreversible phase transition restricts the application of Li3V2O5 cathode materials in lithium-ion batteries. In this paper, co-doped Li3V2O5 nanorod cathode materials were prepared. The one-dimensional structure can relieve the accumulation of strain during charging and discharging process. Also, Co3+ doping can stabilize the structure of Li3V2O5 by forming the more intense Co-O bonds. Furthermore, Co3+ doping expands the cell volume and ratio of V4+ in Li3V2O5. These collectively result in the improved Li+ diffusion coefficient and cycling stability of Li3V2O5. The 1% Co-doped Li3V2O5 (i.e., 1%Co-LVO sample) has a specific discharge capacity of 256.43 mA?偸h/g at a current density of 50 mA/g and a capacity retention rate of 77.3% after 100 cycles, which is 28% greater than that of the pristine Li3V2O5. 1%Co-LVO sample shows a superior capacity fading (i.e., 0.23%/cycle). This paper can provide an effective method for the preparation and performance regulation of high-energy-density lithium-ion cathode material (i.e., Li3V2O5).

Based on an innovative green recycling route for recycling and re-synthesis of spent lithium-ion batteries, LiCoO2 was synthesized by a molten salt method with LiCl-KCl as a molten salt medium and LiOH·H2O and Co2O3 as raw materials, and then the button batteries were prepared for resource recycling. The reaction kinetics of lithium cobalt oxide synthesis and the effect of reaction conditions on the structure and morphology of LiCoO2 were investigated. The battery performance of LiCoO2 was characterized by electrochemical analysis. The results show that the activation energies of the three endothermic reaction processes in the synthesis calculated by the Kissinger model are 34.212 00, 168.539 25 kJ/mol and 221.261 81 kJ/mol, respectively. The product of LiCoO2 has a good hexagonal lattice structure when calcined at 750 ℃ for 6 h. The charge-discharge and cycle performance of the battery were tested at 0.2 C rate and 2.4-4.2 V. The experimental battery prepared by LiCoO2 calcined at 750 ℃ for 6 h has the first charge-discharge specific capacity of 150 mA?偸h/g and 147 mA?偸h/g, the Coulombic efficiency is 98%, and the discharge specific capacity after 50 cycles of charge and discharge is still 129 mA?偸h/g. The battery still has a good charge and discharge performance after rate cycle.

Silicon has attracted wide attention due to its high theoretical specific capacity. However, the huge volume change and poor reaction kinetics in the lithiation process lead to a serious deterioration of its structure, a continuous capacity attenuation and a poor magnification performance, thus restricting its practical application. To solve these problems, silicon/reduced graphene oxide (Si/rGO) nanocomposites with a three-dimensional cage-like conductive structure were designed by an in-situ electrostatic self-assembly and hydrothermal reduction method with commercial Si nano-particles with the size of 60 nm and natural flake graphite. The lithium ion storage performance and energy storage mechanism of Si/rGO nanocomposite were investigated. The results show that Si nano-particles are uniformly encapsulated into a three-dimensional cage-like conductive network structure of rGO, effectively limiting the volume expansion of nano-Si particles and providing the more ion transport channels in the process of lithium ion intercalation/detachment. The specific capacity of Si/rGO nanocomposites is 1 246 mA?偸h/g at 0.1 A/g. The Coulomb efficiency is 98.2% and the capacity retention is 95.5% from fifth cycle, indicating that the nanocomposite has a fast stability behavior. The reversible capacity remains 852 mA?偸h/g, the Coulomb efficiency is 99.9%, and the capacity retention is 68.4% after 200 cycles.

Aqueous zinc-ion batteries (ZIBs) are considered to be prospective candidates in energy storage devices because of their excellent safety, crustal abundance, low cost and environmental benignity. Whereas, the design of a satisfied cathode material with a large specific capacity, superior rate performance and long-cycle life is still a significant challenge for ZIBs. Herein, a new strategy is proposed to use W doped V2O5 as cathode material for aqueous ZIBs. The W doping can effectively enlarge the lattice spacing and ion migration efficiency of V2O5, and the formation of W-O bond can obviously alleviate the capacity decay problem caused by structural damage and low intrinsic conductivity in the cycling process. As a result, the V2O5-W cathode exhibits an excellent capacity of 195.0 mA·h/g after 100 cycles at 0.1 A/g, and an impressive rate capability of 243.0 mA·h/g at the high current density of 1 A/g after 1 000 cycles. This work provides a simple, efficient and feasible strategy for designing high-performance cathode materials in ZIBs.

To explore the potassium storage potentials of polymetallic selenides, nitrogen-doped carbon coated ZnSe/CoSe/SnSe materials was synthesized by a hydrothermal method. The core of polymetallic selenides exhibits an enhanced electrochemical activity, and a cavity in the structure alleviates the volume effect upon cycle when this compound serves as anode materials of potassium-ion batteries. Meanwhile, the conductive coating shell effectively improves the material conductivity and prevents the active substance from agglomeration during potassium storage. Compared with the uncoated material, ZnSe/CoSe/SnSe@nitrogen-doped carbon material has a better potassium storage performance. The discharge specific capacity still maintains 193 mA·h/g after 800 cycles at a current density of 1 A/g. This work could provide a guide for the design and construction of high-performance potassium ion battery anode materials.

Selenides have a higher reversible capacity and a suitable working potential. However, their large volume change during cycling and low conductivity restrict their practical applications. In this paper, FeSe2/Ti3C2Tx composites were synthesized as anode materials for sodium-ion batteries by a simple hydrothermal method. Fe2+ were firstly coordinated with ethylene diamine tetraacetie acid to form chelates, and then FeSe2/Ti3C2Tx composites were synthesized via the electrostatic interaction between Ti3C2Tx and Fe2+ chelates after the hydrothermal reaction. FeSe2/Ti3C2Tx has an open ‘flower petal’ structure, and Ti3C2Tx in the composite provides an intense conductive network for the material and relieves volume expansion. According to the results of the electrochemical test, Ti3C2Tx electrode has a capacity of 455 mA?偸h/g after 150 cycles at 0.5 A/g, while the capacity of FeSe2 electrode at the same current density is only 335 mA?偸h/g after 100 cycles, and the capacity decays rapidly in the subsequent cycles. It is indicated that FeSe2/Ti3C2Tx electrode has superior electrochemical sodium storage performance and cycling stability.

As energy storage materials, transition metal phosphides have attracted recent attention. In this paper, FeP hollow nanorods were fabricated with hydrothermally synthesized MoO3 nanofibers as a template. The chemical composition, morphological structure and synthetic process of such a product were characterized. Its supercapacitive properties as an electrode material were also investigated. The results show that the developed FeP hollow nanorods have a porous nature with the specific surface area (i.e., 277.4 m2/g) and well-defined interior of about 30 nm thick shell due to the stack, aggregation and adhesion of FeP nanoparticles. The FeP hollow nanorod electrode with a unique morphological structure and a large specific surface area has a superior supercapacitive behavior with the maximum specific capacitance of 243.6 F/g, remarkable rate capability as well as outstanding cycling stability. The capacitance decay of only 13.8% can be achieved after consecutive charge/discharge for 10 000 cycles at a large current density of 5 A/g. The electrochemical performance of FeP hollow nanorods is better than that of some Fe-based supercapacitor electrode materials previously reported.

Supercapacitors have a wide range of potential applications in new energy storage and electric cars due to their high capacity, high power density, and extended cycle life, and the electrode materials are a key to enhancing the supercapacitor performance. NiCoMnSe electrode materials were prepared by a simple low-temperature hydrothermal reaction method and a heat-treatment selenization method using ZIF-67 as a template. The optimum electrochemical performance was obtained via adding carbon nanotube (CNT) or graphene oxide (GO) to the ZIF-67 template. The results show that the optimum NiCoMnSe/CNT electrode has a specific capacitance of 624.0 F/g at 1 A/g and a multiplicative performance of 90.1% at 10 A/g. The capacity retention rate is 88% at 15 A/g for 1 000 cycles. This superior capacitive performance is attributed to the presence of CNT introducing additional mesopores around NiCoMnSe, thus enhancing the contact between the electrolyte and the active material. The NiCoMnSe/CNT/activated carbon device exhibits a high energy density (43.3 W?偸h/kg) at a power density of 800 W/kg and a good capacity retention (i.e., 91.4% after 1 000 cycles) due to the asymmetric nature of the supercapacitor.

The applications such as electric vehicles require a high energy density in lithium-ion batteries. LiNi0.9Co0.1O2 has attracted much attention, which has a potential to be next-generation cathode material due to its high specific capacity and reasonable cost. However, some related issues such as Li/Ni mixing, microcracks and surface side reactions caused by H2-H3 phase transformation result in a poor cycling stability for LiNi0.9Co0.1O2. In this paper, the microstructures of LiNi0.9Co0.1O2 by W6+ doping were regulated by an effective method to adjust the surface energy of the primary particles and transform the disordered and irregular-shape primary particles into the well-ordered radially-aligned elongated shape particles. This microstructure feature can suppress the stress accumulation and the formation of micro-cracks in LiNi0.9Co0.1O2, and provide abundant diffusion channels for Li+, thus improving the cycling stability and rate performance of LiNi0.9Co0.1O2 cathode materials. The discharge capacities of 1% (in mole fraction) W-doped LiNi0.9Co0.1O2 are 231.2 mA·h/g at 0.1 C and 213.3 mA·h/g at 0.5 C, respectively, with a high capacity retention of 93% after 150 cycles. This microstructure regulation strategy provides an effective approach for improving the cycling stability of LiNi0.9Co0.1O2 Ni-rich cathode materials.

All-solid-state lithium-ion batteries constructed with solid-state electrolytes have extremely high safety and reliability, which are an existing research hotspot in lithium-ion batteries. It is thus a great significance to develop inorganic-polymer composite solid electrolytes. In this paper, Li7La3Zr2O12 (LLZO) nano-powders were prepared by a sol-gel and ball milling method. Also, a solid-state composite polymer electrolyte with LLZO as an active filling material and polyethylene oxide (PEO) blended with polyethylene partial fluoride (PVDF) was prepared by a solution pouring method. The samples were characterized by field emission scanning electron microscopy and X-ray diffraction. The results show that LLZO/PEO/PVDF solid-state composite polymer electrolyte (SCE) membrane with 10% (in mass fraction) LLZO has a high ionic conductivity (8.93×10-5 S/cm) and a stable electrochemical window (4.9 V). The rate capabilities and cycle performance of LiFePO4/Li all-solid-state lithium battery with 10%LLZO both are improved. At 60 ℃, the capacity recovery rate is 99.4%, and the capacity retention rate after 100 cycles is 84.1% at 0.2 C.

In order to improve the electrochemical performance of cathodes for low-temperature solid oxide fuel cells, two kinds of La0.6Sr0.4Co0.2Fe0.8O3-δ/Ce0.9Gd0.1O2-δ (LSCF/GDC) cathodes with a multifunctional hierarchical scaffold structure were prepared. The microstructure and electrochemical properties of the cathodes were investigated. The results show that the GDC primary scaffold with a porosity of 80.5% fully ensure the construction of LSCF or GDC secondary scaffold, subsequent loading and oxygen diffusion in the working state. Based on the analyses of distribution of relaxation times for the electrochemical impedance spectra, the cathode with LSCF nanoparticles as a secondary scaffold has a total polarization resistance of only 0.236 Ω·cm2 at 600 ℃ due to the abundant reactive sites and unobstructed electronic conduction, and the GDC nanoparticles loading promotes the adsorption/dissociation of oxygen. The hierarchical scaffold cathode has a simple process and excellent oxygen reduction performance, which can promote the further development of low-temperature solid oxide fuel cells.

The double perovskite oxides are widely investigated as cathode materials for solid oxide fuel cell (SOFC) due to their superior ionic electron conductivity. In this work, Pr0.9Ca0.1Ba1-xCaxCo2O5+δ (0≤x≤0.3, PCBC) was prepared by a modified complexing sol-gel process. Based on the electrical conductivity results, Ca ion co-doping can effectively improve the conductivity of the material. The electrochemical performance results indicate that the cathode with x of 0.2 has the optimum oxygen catalytic activity, and the polarization impedance is only 0.069 ?偸cm2 at 700 ℃. The oxygen vacancy formation energy, density of states, as well as O s and O p band center of PrBaCo2O5+δ, Pr0.75Ca0.25BaCo2O5+δ, and Pr0.75Ca0.25Ba0.75Ca0.25Co2O5+δ materials were calculated based on the GGA-PBE function. It is indicated that Pr-site doped with Ca can reduce the oxygen vacancy formation energy, while Ba-site doped with Ca can increase the oxygen vacancy formation energy. The calculation results of O p band center show that the strategy of Ba-site doped with Ca can effectively increase the oxygen reduction activity. The co-doping strategy of double perovskite can improve the thermal expansion, conductivity, electrochemical performance, and long-term stability of the material.

The study of weathering alteration of phyllosilicate minerals is of great significance for understanding the chemical cycle of the earth surface, soil formation and environmental changes. A phlogopite from Xinjiang, China was used as a raw material to control the oxidation environment, pH value, ion species and concentration of sulfuric acid solution in the process of phlogopite vermiculization. The phase, composition release law, spectroscopic properties and thermal properties were characterized by X-ray diffraction, inductive coupled plasma emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetry- differential scanning calorimetry, respectively. The results show that the degree of vermiculite increases with the increase of Mg2+ ions concentration in the solution, but the less conversion effect exists at a certain H2O2 content in the solution. The conversion effect can be enhanced after the use of sulfuric acid to adjust the solution pH value, because the acidic environment can improve the oxidation capacity of hydrogen peroxide and the increase of SO42- ions concentration. The more jarosite substances are formed, thus accelerating the process of vermiculization.

It is of great significance for the improvement and utilization of fly ash to reduce the accumulation pollution of coal based solid waste. In this work, a porous high-content iron fly ash sorbent named KIFA was obtained via CaO hydration, addition of pore-making agent and binder, and oxidation modification by NaClO. This sorbent KIFA with an optimized pore structure can promote the formation of K2FeO4. The fixed-bed evaluation results show that the KIFA has the maximum SO2 removal ability at 700 ℃, 5% O2 and 500 mg/m3 SO2, and the breakthrough time and sulfur capacity of the removal efficiency of > 93% are 111.8 min and 93.58 mg/g, respectively, having the ultra-low emission standard of 35 mg/m3. According to the characterization results of fresh and used KIFA, K2FeO4 is a main active component in removing SO2 by KIFA, and Fe(VI) provides the oxidation site, which oxidizes SO2 to SO42-. NO can promote the forward desulfurization reaction. NO, SO2 and CaO can form an intermediate product of NO3SO3Ca, which can be converted into SO42-, thus improving the removal efficiency of SO2.

To obtain easily recycled photocatalyst and improve the reusing practicability for waste water treatment, Bi2O3 films were prepared by a plasma spray-chemical vapor deposition method , and the effects of deposition temperature and heat-treatment temperature on the morphology and phase composition of Bi2O3 films were investigated. The morphology and composition of the films were characterized by field-emission scanning electron microscopy, X-ray diffraction and high-resolution transmission electron microscopy. The band gaps of α/β-Bi2O3 at different heat treatment temperatures were determined by ultraviolet-visable diffuse reflectance spectrometry. The results show that the deposition temperature and heat-treatment temperature affect the microstructure of Bi2O3 films and the proportion of α and β phases, while the influence of deposition temperature is more dominant rather than that of heat-treatment temperature. The proportion of β phase gradually converts to α phase and the band gap of α-Bi2O3 and β-Bi2O3 increases when the heat-treatment temperature increases. The Bi2O3 films exhibit a good photocatalytic degradation performance for Methyl Orange and Bisphenol A.

Although some ceramic materials are prepared via cold sintering, the relative density of zirconia as an important structural ceramic is still low. To improve the relative density of cold sintered zirconia ceramics, metastable nanocrystal zirconia flakes were used as a starting powder. ZrO2 sheet containing 56% tetragonal phase was prepared with graphene oxide as a template and trihydroxymethyl aminomethane as a precipitator. The influence of sintering additives, temperature, pressure and liquid content on the relative density and microstructure of ZrO2 was investigated. The results show that the relative density of approximately 70% is achieved under the condition of cold sintering with HCl as a sintering additive, 300 ℃, 500 MPa and liquid content of 20% (in mass fraction), which is much higher than the previously reported relative density of cold sintered zirconia. The increase of relative density is mainly due to the phase transformation of the sintered metastable ZrO2 and the particle rearrangement and solution-precipitation of the flake powder. The Young modulus and flexural strength of cold-sintered ZrO2 ceramics are 24 GPa and 20 MPa, respectively, due to the decrease of porosity.

High-efficiency, green, stable and economical texturing molecules and the relative additive composition are considered as one of the key tasks to obtain a light trapping structure with an ultra-low reflectivity and to improve the photoelectric conversion efficiency of monocrystalline silicon solar cell. In this work, polyphenyl skeleton was used to strength the interfacial interaction between silicon crystalline face and texturing molecules, while sulfonic, hydroxy and alkoxy groups regulate the texturing sites. Sodium 6-naphthalene disulfonate, sodium 2-hydroxy-7-naphthalene sulfonate, sodium dodecyl diphenyl ether sulfonate and sodium lignosulfonate were selected to investigate their texturing effects. The results show that larger molecular size, dispersed polyphenyl skeleton, flexible molecular structure, abundant hydroxyl and alkoxy groups for polyphenyl sulfonate derivatives facilitate the generation of a continuous, uniform and dense pyramid structure on monocrystalline silicon surface. Based on the comparative experimental results at different reaction parameters (i.e., texturing molecule structure, concentration, reaction time and temperature), sodium lignosulfonate was selected as an effective texturing reagent. In a low mass fraction range of 0.000 6%-0.06%, the single use of sodium lignosulfonate can lead to a low reflectivity of 15.84%-26.94%. A low-concentration and high-stability additive composition with 0.015% (in mass fraction, the same below) sodium lignosulfonate, 1.1% sodium dodecylbenzene sulfonate and 2.0% 2-hydroxy-β-cyclodextrin can be obtained via systematic orthogonal experiments in the presence of a surfactant and an antifoaming agent. A desired texturing surface featured with a uniform, dense pyramid structure sized at 1.7-1.9 μm and an average reflectivity of 9.89% occurs at 75-85 ℃ for 200-400 s when adding this additive into 0.65% NaOH aqueous solution as a corrosive agent. This work can provide a reference for the development of green, efficient and practical additives for texturing on monocrystalline silicon based on polyphenyl sulfonate derivatives as a texturing agent.

As electrode materials for supercapacitors, transition metal oxides have some advantages of high theoretical specific capacity, good chemical stability, and abundant sources. However, its inherent poor conductivity, low utilization rate, and poor cycle stability greatly hinder its practical application. Oxygen vacancies in metal oxides can effectively regulate their electronic properties, reduce the band gap, and increase their electrical conductivity, thus significantly improving their electrochemical rate performance. Furthermore, oxygen vacancies can induce a low oxidation state of the metal, provide more active sites for surface redox reactions, and improve its electrochemical storage capacity. The review introduced various preparation methods and characterization techniques of oxygen-vacancy abundant transition metal oxides. This review also represented the latest advances of various metal oxides with oxygen vacancies from single metal oxides, bimetal oxides, and heteroatom doped metal oxides to achieve the superior performance for supercapacitors. In addition, some challenges and opportunities for the further development of metal oxides in electrochemical energy storage were also pointed out.

The loss of non-renewable resources and the increasingly severe environmental problems have attracted much attention. It is thus important to develop and utilize renewable resources such as biomass energy and solar energy. The application of photocatalytic technology in biomass meets the requirement of social sustainable development. This review represented the research progress on the biomass-modified photocatalyst and biomass involved in photocatalytic reforming. The mechanism of biomass-modified photocatalytic materials engaging in the photocatalytic reaction was introduced. The effectiveness of biomass and biomass-derived substrates in photocatalytic reforming reaction systems was investigated. Some methods used for the preparation and characterization as well as the structure-activity relationship between biomass and the photocatalytic reaction system were discussed. In addition, some aspects and potential research prospects in the application of biomass in photocatalytic systems were also given.

Crystallization is an important stage in the synthesis of materials and in the formation of minerals in natural environment. This review represented some typical non-classical nucleation pathways proposed in recent years, i.e., spinodal decomposition, pre-nucleation clusters, and amorphous precursors. The multiple nucleation pathways coexisting in the same system were discussed. The theoretical system construction of incorporating non-classical nucleation into classical nucleation theoretical framework was analyzed. In addition, the future research aspects of crystal nucleation were also prospected. This review provides a perspective aspect on crystal nucleation - classical and non-classical nucleation coexisting in a common system, which is promising to further clarify the theory of crystal nucleation.