In recent years, the composite hydrogels composed of micro-nano bioactive glass (MNBG) and gelatin are widely used in tissue regeneration. However, the relationship between hydrogels and MNBG in terms of mineralization and degradation is still unclear. In this paper, gelatin based composite hydrogels with different concentrations of MNBG were prepared, and the effect of MNBG on the mineralization and degradation properties of composite hydrogel was investigated by in vitro experiments. The results show that the composite hydrogel does not affect the bioactive ion release of MNBG, and the formation of negative curvature interface by a high concentration of MNBG aggregates is a necessary condition for composite hydrogels to mineralize. In addition, increasing the concentration of MNBG and quickly mineralizing to form hydroxyapatite layer can effectively reduce the degradation rate of gelatin based composite hydrogel.

In recent years, borosilicate bioactive glass (BBG) is widely studied due to its osteoinductive activities. However, the ions accumulated in the extracts can induce cytotoxicity and hemolysis when evaluating the biological properties of the degradable materials using the extracts of the materials. In this paper, the BBGs were prepared at different ratios of B2O3 (0B, 1.5B, and 3.0B samples), and bone cements were fabricated by mixing the BBGs with 30% (in mass fraction) citric acid. The cytotoxic and osteogenic effects of the bone cements extracts were evaluated using human bone marrow mesenchymal stem cells (hBMSCs), and the bone healing effects of the bone cements were evaluated using a rat femoral defect model, respectively. The results show that the extracts of bone cement formed at a greatest ratio of B2O3 in the bioactive glass can induce a maximum inhibitive effect on the proliferation and osteogenesis of hBMSCs in vitro. However, the degradation and bone healing effect of the bone cement increase directly with the ratio of B2O3 in BBG upon transplantation. Also, there is a huge discrepancy with the in vivo and in vitro evaluation systems for the biodegradable biomaterials. Understanding the mechanisms of the different biological effects of BBG in vitro and in vivo will provide some guidance for the design of a more effective borate-containing bioactive materials and the construction of a better evaluation system for bioactive materials in vitro, thus facilitating the clinical applications of BBG.

Bioglass (BG) microspheres with a constitution of CaO-SiO2-P2O5 demonstrate promising applications in bone repair. It has been proved that the cerium ion incorporation in bioglass structure can provide materials with additional antioxidant, anti-inflammatory and angiogenesis functions. In this study, cerium-incorporated bioglass (Ce-BG) microspheres were prepared via a spray drying process. The effects of Ce content on the phase composition, degradation performance and in vitro bioactivity of Ce-BG microspheres were investigated. The results show that all microspheres are uniform in element distribution with relatively smooth surfaces and a high degree of sphericity. The Ce incorporation introduces a small amount of CePO4 and CeO2 crystalline phases. Along with the increase of Ce content, the degradation rate of Ce-BG microspheres slows down, and the effect of degradation products on the increase of environmental pH value is alleviated, and the pH value was found to be the lowest after 7 d of immersion for Ce-BG microspheres with mole ratio of Ce and Ce+Ca of 0.03:1.00 in Tris-HCl buffer. Ce-BG microspheres with different Ce content have good ability to induce apatite deposition in vitro.

In the field of bone repair, the process of bone repair can be accelerated via building a natural bone regeneration microenvironment. An important part of the cellular microenvironment is the bioelectrical signal, which exists in various tissues of the body and plays a key role in regulating stem cell differentiation and tissue repair. The unique electrical properties of electroactive materials can be used to simulate a regenerative electrical microenvironment in bone defects, stimulating the body inherent repair potential and accelerating the repair of bone defects. According to the distinction of applied electrical signals, this review represented recent research work on the use of various types of electroactive materials to promote bone repair in terms of ferroelectric, piezoelectric, electret and conductive materials, providing some ideas to further enhance the therapeutic effect.

Micro-nano bioactive glass (MNBG) has a good biological activity and is widely used in tissue engineering. In recent years, a variety of metal ions are incorporated into the network structure of materials during the preparation of MNBG, thereby endowing MNBG with various physicochemical and biological functional properties. However, the exact mechanism of interaction between the ion release products of MNBG and human cells is not fully clarified. This review represented the preparation methods and processes of MNBG and the application of its lysates in bone and tooth and other hard tissue repair, skin tissue repair, cancer treatment and cell imaging. This review could provide a reference for the further development of MNBGs applied to the biomedical field.

Hydroxyapatite (HA) is the main inorganic constituent of human hard tissue. It can effectively accelerate the repair process of hard tissue defects due to its high bioactivity and biocompatibility. Ion doping is an effective approach to enhance the bioactivity of HA materials. On this basis, dual-ion substitution can make HA materials have a higher simulation to nature bone in composition and some functional features (i.e., antitumor ability, antibacterial activity, pro-angiogenetic capacity, immunoregulatory and medical imaging capability). Dual-ion substitution greatly extends the applications of HA materials in bone tissue engineering. This review summarized the synthesis methods and their principles of dual-ion substituted HA (DIHA) materials, represented the applications of DIHA materials in hard tissue engineering, and finally proposed the future development direction of DIHA materials.

The inorganic composition of natural bone tissue is mainly calcium phosphate and consists of a variety of other elements necessary to maintain life activities to ensure the normal growth and development of bone tissue. In the preparation of calcium phosphate biomaterials, elemental doping can effectively regulate the morphology of calcium phosphate and have antibacterial properties, immune regulation, angiogenesis, osteoinduction and other biological functions. This review represented the regulatory effects of single-doping or co-doping of Mg, Zn, Sr, Cu, Ag, Co, Ag, Mn, and rare earth elements as well as Se, Si, and F in a variety of calcium phosphate on the structural morphology and biological function of materials. In addition, the future research work of calcium phosphate biomaterials was also proposed to provide a reference for the future research of novel scaffolds in tissue engineering.

Solid oxide cell (SOC) plays a pivotal role in the reversible conversion of electricity-gas-electricity. The seawater electrolysis through reversible SOC is proven to be an effective approach to the intermittent power generation such as offshore wind power and photovoltaic power generation. In this paper, a flat-tube SOC stack was tested to analyze the reversible performance for SOC stack fueled with seawater/H2 under different operating conditions (i.e., water vapor content and current density). The results show that the degradation rate in electrolysis mode is minimal at a current density of 100 mA·cm-2, a humidified temperature of 90 ℃ (volume fraction of water vapor is 65%) and 750 ℃. The minimum voltage degradation rate in fuel cell mode is attained at a current density of 100 mA/cm2, a humidified temperature of 86 ℃ (volume fraction of water vapor is 56%) and 750 ℃. The efficiency of the stack in reversible mode is 95.2% at 100 mA·cm-2. It is indicated that this study could provide a reference for the application of reversible SOC stacks in seawater environment.

Sodium ion batteries (SIBs) have a great potential in electrochemical energy storage. However, the development of SIBs anodes with high specific capacity and cycle stability is still a challenge. In this paper, a VS2/Ti3C2Tx MXene sodium-ion battery anode was synthesized via a solvothermal strategy to form VS2 nanosheet in situ anchoring on Ti3C2Tx MXene structure. The agglomeration of VS2 during growth process was suppressed based on in-situ confinement growth mechanism by Ti3C2Tx MXene. In addition, the charge transfer kinetics of VS2 is also largely boosted by the stable chemical coupling between VS2 and Ti3C2Tx MXene. As a result, the VS2/Ti3C2Tx MXene composite exhibits a high specific capacity of 340 mA·h/g at a high current density of 10 A/g, as well as a stable long-term electrochemical performance after 2 000 cycles at a current density of 5 A/g. This design of composite provides an effective approach for the development of anode materials for sodium-ion batteries with a high energy density and a high power density.

Disadvantages such as side reactions and dendrite growth in zinc electrodes restrict the application of zinc electrodes in energy storage. A high electrochemical performance zinc-attapulgite (i.e., Zn-ATP) composite electrode was prepared via a strategy of coating attapulgite on the surface of zinc electrode. The results show that the porous functional coating is formed by the stacking of ATP rod crystals, and it has high mechanical strength properties. The assembled Zn/Zn-ATP symmetrical battery and Zn-ATP/manganese dioxide full cell both have high performances of charge and discharge cycling. The hydrogen evolution side reaction of the electrode is significantly suppressed under the work of ATP coating. Meanwhile, the formed Zn plate crystals flatly precipitate on the electrode surface, thus effectively reducing a possibility of the dendrites penetrating the battery membrane.

It is important to improve its electrical and optical performances of transparent conductive thin films via constructing a double-layer homogeneous heterostructure with a wide and narrow band gap. The electronic structure, optical properties, carrier mobility, charge distribution, and energy band alignment of intrinsic and doped SnO2/SnSe2 were calculated using the first-principles based on density functionalities. The results show that a potential difference existing in the intrinsic and doped SnO2/SnSe2 electronic structures causes the electrons in the system to transfer to the interface or SnSe2, and the electrons at the interface form a two-dimensional electron gas (2-DEG) in the interface gap and move at a high speed at the interface, thereby increasing the mobility of carriers, while the electrons at SnSe2 have a corresponding increase in mobility due to the absence of impurity ion scattering. The mobilities are 772.82, 5 286.04, 2 656.90 m2/(S·V) and 17 724.60 m2/(S·V), respectively, and the optical transmittance is >80%.

Printed circuit boards (PCBs) are usually required to be integrated and miniaturized by a variety of applications, such as 5G microstrip antenna and millimeter wave radar, which require the used dielectric substrate materials with a low dielectric loss (Df) and a high dielectric constant (Dk). The composite substrate prepared by filling dielectric ceramics into organic polymers has good machinability and superior dielectric properties, which is regarded as the most promising solution. However, the physical and chemical indexes, dielectric properties of the ceramic filler and its compatibility with organic resins are three key factors affecting the comprehensive properties of organic/inorganic composites. In this paper, a micron-spherical filler with a high sphericity and a high crystallinity was prepared by a special spheroidization technology with titanium dioxide material with superior dielectric properties(i.e., Dk ≈110, Df ≈ 0.001, dielectric constant temperature coefficient (α) ≈ -700×10-6 ℃-1). The compatibility between the filler and organic resin is improved after the surface modification of TiO2 filler. Also, the dielectric constant temperature coefficient of TiO2 filler is regulated by Al2O3 doping. The composite substrate filling with 20% (in mass) Al2O3 exhibits the superior properties (i.e., Dk=10.2, Df=0.001 9, and α= -405×10-6 ℃-1). This indicates that the as-prepared ceramic filler has the promising characteristics for potential applications of 5G high-frequency, high-dielectric PCBs.

It is important to enhance their performance of supercooling and low thermal conductivity in hydrate salt phase change materials. A hydrophilic silicon carbide (nano-SiC) was prepared via treating SiC nanoparticles in HF/HNO3 with Na2SO4·10H2O-Na2HPO4·12H2O eutectic hydrated salt as basic materials, and the phase change nanofluids materials (nano-SiC EHS PCMs) with Na2SiO3·9H2O and nano-SiC were composited. The results show that the modified nano-SiC can be dispersed in EHS PCMs. The synergistic effect of Na2SiO3·9H2O and nano-SiC can reduce the supercooling degree to 0.3 ℃ without the phase separation. The thermal conductivity of nano-SiC EHS PCMs enhances both in solid and liquid. The energy storage time of EHS PCMS with 0.2% (in mass) nano-SiC is decreased by 21.8%. The enthalpy of melting and crystallization of EHS PCMs with 0.15% nano-SiC is 267.3 J/g and 231.4 J/g, respectively. The enthalpy of nano-SiC EHS PCMs is stable after 1 000 heating and cooling cycles, indicating that nano-SiC EHS PCMs have a great thermal cyclic stability.

To provide direction and guidance for the microstructure design and development of sealing materials for high-performance intermediate-temperature solid oxide fuel cell, a Al2O3/BaO-CaO-B2O3-Al2O3-SiO2 glass-ceramic (BCBAS)-based composite sealing material with superior mechanical properties and a high thermal conductivity was prepared via tape casting. According to the analysis by scanning electron microscopy and X-ray diffraction, the lamellar Al2O3 is regularly distributed in the BCBAS glass-ceramic matrix. The main crystallization phase of BCBAS glass transforms from Ca0.1Ba0.9SiO3 into Ba1.55Ca0.45SiO4 and BaAl2Si2O8, and further into BaAl2Si2O8 and BaAl2O4 phases when the lamellar Al2O3 content increases from 0 to 25% (in mass fraction). The thermal conductivity of biomimetic sealants increases from 0.892 W/(m·K) to 1.255 W/(m·K), and the bending strength and Vickers hardness with higher than 10 of the Weibull modulus β increase from 96 MPa to 140 MPa and 444 HV to 677 HV as the lamellar Al2O3 content increases from 0 to 25% (in mass fraction), indicating the mechanical properties and thermal conductivity of the sealant. The sealing tensile strength of the biomimetic sealant with the mass fraction of lamellar Al2O3≤20% maintains above 4 MPa. The composite with 20% Al2O3-80% BCBAS glass exhibits the superior comprehensive properties (i.e., thermal conductivity of 1.203 W/(m·K), bending toughness of 136 MPa, Vickers hardness of 677 and sealing strength at 4.22 MPa), thus being a potential candidate for application of intermediate- temperature solid oxide fuel cell.

Photofenton technology is one of the effective means to treat organic wastewater. Developing photofenton catalysts with a higher catalytic efficiency is always a hotspot. A BiOI/MIL-100(Fe) nanocomposite with a visible-light response was synthesized by a facile hydrothermal-co-precipitation method. The as-synthesized BiOI/MIL-100(Fe) nanocomposite was characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscopy, UV-vis diffuse reflectance spectroscopy and N2 adsorption-desorption analysis, respectively. The BiOI/MIL-100(Fe) nanocomposite exhibits a better photo-Fenton activity rather than pure BiOI and MIL-100(Fe) for tetracycline degradation under visible-light irradiation. In particular, the composite (BiOI/MIL-100(Fe)-2) has the maximum efficiency when a content of MIL-100(Fe) is 5.2% (in mass fraction). The formation of BiOI/MIL-100(Fe) heterojunctions between BiOI and MIL-100(Fe) is beneficial to the transfer and separation of charge carriers. The photogenerated electrons accelerate Fe2+/Fe3+ cycle and create the reductive reaction of H2O2. The enhanced performance of BiOI/MIL-100(Fe) nanocomposite is ascribed to a synergic effect for photocatalysis and Fenton reaction.

The application and performance of low-grade limonite tailings (LT) from Yeshan Iron Mine (Tongling, China) were investigated for the formaldehyde purification at ambient temperature. According to the composition analysis of the tailings, the presence of minerals like nanoneedle hematite and quartz with a great specific surface area is suitable as a catalyst carrier. In this paper, birnessite (Bir) was loaded onto the surface of LT particles via chemical reduction to prepare a catalyst for formaldehyde removal with different manganese loads (x-Bir/LT). The results show that the catalyst has a good formaldehyde degradation ability. The removal efficiency of 27.3-Bir/LT is still 97.2% after 600 min at an initial formaldehyde concentration of 1.2 mg/m3 and a gas hourly space velocity of 41.6 m/s, thus having a long-term stability and a water resistance. According to the analysis by in-situ infrared spectroscopy, formaldehyde reacts on the catalyst surface via being adsorbed by surface hydroxyl groups and then oxidized to H+ and HCOO-, which further decomposes into CO2 and H2O through hydroxyl and surface reactive oxygen species oxidation. Also, LT provides a large number of L-acid sites for the catalyst, improving the catalytic oxidation performance of the composite catalyst. Using limonite tailings as a catalyst carrier can enhance the catalytic oxidation performance of the composite catalyst. This work provides a technical reference for its application in indoor formaldehyde pollution control.

Reversible protonic ceramic electrochemical cell (R-PCEC) is an emerging and efficient energy conversion device that can convert chemical energy into electrical energy and electrical energy into chemical energy. The reversible operation of R-PCEC in the dual mode of fuel cell and electrolytic cell is highly flexible and is one of the most promising ways for efficient energy conversion and storage. However, for R-PCEC, the electrolyte conductivity, catalytic activity of the cathode and anode, and durability under actual operating conditions are the main factors restricting its performance. This review introduced the research and development status of each component of R-PCEC in detail, including electrolyte materials, hydrogen electrodes, and air electrodes, as well as mainly focused on the latest progress on material requirements, electrode performance and reaction mechanism of air electrodes for reversible batteries. In addition, the future developments on R-PCEC were also prospected.

Proton-conducting reversible solid oxide cells (P-RSOCs), capable of conversion of chemical energy and electrical energy with a high efficiency and a low cost due to the low activation energy for proton transport, low operating temperature and fuel flexibility, is considered as one of the most promising electrochemical devices for energy storage and conversion. This review represented recent research progress on P-RSOCs. The material systems and fabrication processes of electrolytes and electrodes were discussed. The application prospect and future direction of P-RSOCs were analyzed as well. The perovskite-based oxides are regarded as the critical materials of P-RSOCs due to the diversified composition and modification methods. The fuels flexibility, electrolyte-electrode interface, and the long-term stability are challenges for the development of P-RSOCs.

As an advanced electrochemical energy conversion device, solid oxide electrolytic cell (SOEC) can achieve the hydrogen/hydrocarbon fuel gas precipitation at the electrode side through reversible electrochemical process of solid oxide fuel cell (SOFC). SOEC is regarded as one of the most promising systems in promoting large-scale hydrogen production and energy structure optimization as well as realizing our "double carbon" goal due to its simplicity, fuel flexibility, low energy consumption and high system efficiencies (85%-95%). This review represented the research status on the material selection and service performance for the key components (i.e., fuel electrode, solid electrolyte and oxygen electrode) of SOEC. Moreover, the performance parameters (i.e., current density, voltage decay rate, impedance, conductivity and hydrogen production rate) were summarized. In addition, the application potential of SOEC technology in the future hydrogen production from electrolytic seawater as well as the future development of key component materials such as composite electrode were also proposed.

Energy storage and fuel cell power generation are the most important development directions for realizing the carbon neutrality goal in China. Reversible solid oxide cells (i.e., RSOCs) are promising electrochemical energy conversion devices with a high efficiency and a low emission. The polarization resistance of oxygen electrode is large, and oxygen reduction/evolution reaction (ORR/OER) is sluggish. A lower oxygen exchange rate is considered as a main rate limiting step in reactions of RSOCs, restricting the efficiency and performance. This review summarized various techniques for characterizing the oxygen surface exchange coefficient (k), and introduced the working principle, merits and research progress of optical transmission relaxation approach. Also, this review discussed the factors like defect chemistry, surface chemistry, orientation, grain boundary/grain size and the crystallinity on the oxygen exchange kinetics and catalytic activity of oxygen electrode, and gave some advices for the future research.