The stable and reliable red phosphor with high-photon energy emission (620-650 nm) is critical for the fabrication of the phosphor-converted white light-emitting diode (WLED) with low correlated color temperature and high color rendering index. Mn ⁴⁺-activated phosphor is an emerging kind of red-emitting phosphor for WLED. Herein, the energy levels transition and photoluminescence characteristics of the Mn ⁴⁺ ion were introduced; then, the preparation, crystal structure and luminescent properties of as-far reported seven kinds of Mn ⁴⁺-doped oxyfluoride red phosphors (such as Na₂WO₂F₄:Mn ⁴⁺) containing d ⁰, d ¹⁰ or s ⁰ cations were reviewed. Currently, only in quite rare case of oxyfluoride, Mn ⁴⁺ was found to exhibit strong R-line emission, with local coordination remaining as either [MnF₆] or [MnO₆]. The studies on the chemical stability and quantum efficiency of Mn ⁴⁺-doped oxyfluoride phosphors are still insufficient. Finally, we prospected the future development of Mn ⁴⁺-doped oxyfluoride phosphor.

In recent years, ternary layered carbide/nitride MAX phases and their derived two-dimensional nanolaminates MXenes have attracted extensive attention. The crystal structure of MAX phase is composed of M_n+1X_n unit interleaved with layers of A element. MAX phases combine good properties of metal and ceramic, which makes them promising candidates for high temperature structural materials, friction and wear devices, nuclear structural materials, etc. When etching the A-layer atoms of the MAX phase, the two-dimensional nanolaminates with the composition of M_n+1X_nT_x (T_x is surface termination), i.e. MXene, is obtained. MXenes have wide range of composition, and tunable physical and chemical properties, which endow them great potential in the applications of energy storage devices, electromagnetic shielding materials, and electronic devices, etc. In this paper, the research progress of MAX phase and MXene was introduced in terms of composition and structure, synthesis methods, and properties and application. Furthermore, the research prospects of this large family of materials were discussed.

Inspired by the lotus leaves in nature against contaminants in the muddy environment, superhydrophobic phenomena has attracted tremendous attentions among the research communities, and triggered the researchers to fabricate an artificial superhydrophobic surface for real-time applications. In this paper, the development of bioinspired materials is combed in accordance with time evolution. Besides, the advantages/disadvantages of numerous preparations in superhydrophobic coating are discussed through the recent researches. In addition, the recent advances of superhydrophobic applications are summarized, such as self-cleaning behavior, anti-icing properties, anti-corrosion performance and oil/water separation. Particularly, this review introduces the mechanism and implementation of anti-icing properties by superhydrophobic coating. As for superhydrophobic coating, current challenges are pointed out and its future development for applications is prospected. Overall, this review provides a reference for research and development of superhydrophobic coatings.

With the development of wearable flexible electronic technology, the demand for flexible sensor with high sensitivity and wide sensing range is gradually increasing. The application of suitable conductive materials with high electrical conductivity and high flexibility as sensitive materials for sensors is the key to obtain high performance sensors. In recent years, MXene materials have become very promising sensitive materials due to their good conductivity, high flexibility, good hydrophilicity, and controllable synthesis. The types of MXene-based flexible force sensors, microstructure design of sensitive materials, sensing performance, and sensing mechanism analysis have been expound and summarized in this paper.

In recent years, hexagonal boron nitride (h-BN) two-dimensional (2D) atomic crystal has attracted considerable attention due to its unique structure, novel property and potential applications. The synthesis of high quality h-BN determines how far we can go for property research and practical applications. However, the sizes of h-BN domains obtained by mechanical exfoliation were limited to several micrometers. Transition metal substrates are usually used in the CVD growth of 2D h-BN layers, and thus a transfer process is required for fabricating h-BN-based electronic devices. Therefore, it is strongly desirable to directly synthesize 2D h-BN on dielectric substrates. In this article, we review recent process on the direct growth of h-BN by CVD, MOVPE, PVD on different dielectric substrates, including silicon-based substrates, sapphire, quartz, etc. Several approaches, such as, increasing substrate temperature, oxide-assisted nucleation, and surface nitridation were adopted to directly grow h-BN on dielectric substrates. Besides, we also summarized the main applications of 2D h-BN grown on dielectric substrates.

Silver nanowire transparent conductive film is one of the new indium-free electrode materials. It has attracted increasing attention from academia and industry due to its superior optoelectronic properties and excellent flexibility. It has been employed in a wide variety of applications in displays, touch panels, solar cells, smart heaters, electromagnetic interference shielding, and so on. However, silver nanowire transparent conductive film has a serious stability issue in service, for example, break or spheroidization above 300 ℃ under fulfidation, accelerating the degradation under ultraviolet light, pores for mation or even breakdown due to electromigration. In this review, the degradation phenomena is thoroughly introduced, the degradation mechanisms is analyzed, and the remedy strategy of degradation is discussed.

Chromogenic materials are capable of optical change reversibly in response to physical stimuli (e.g., electric field, temperature, illumination, and atmosphere). Among them, electrochromic materials are expected to be widely used in smart windows, screen displays, multi-functional energy storage devices and other fields due to their characteristics such as large adjustment range, fast response rate, high coloring efficiency and good cycle stability. However, compared with semi-solid-state electrochromic devices that are difficult to package and organic electrochromic materials that are prone to denaturation and failure, inorganic all-solid-state electrochromic materials and devices have better comprehensive application. This paper focuses on the typical inorganic all-solid-state electrochromic materials and devices, presents a brief review on the current preparation methods of each structure layer of electrochromic devices and compares its advantages and disadvantages, introduces in detail the main alternative electrochromic materials and its key performance evaluation index, and explains the principle of several representative electrochromic devices, proposes to use transparent flexible electrodes with both high light transmittance, low surface resistance and excellent bending fold to replace the traditional rigid substrate in order to realize multi-field responsible device application development. Finally, the application prospect of inorganic all-solid-state electrochromic devices is prospected from the perspective of performance bottleneck, process difficulty and industrialization opportunity, which provides reference for the industrialization process of electrochromic devices.

High-entropy ceramics, a novel class of single-phase ceramic solid solutions consisting of near-equimolar multielement species, are recently attracting tremendous attentions. Especially, the transition metal non-oxide high-entropy ceramics, such as transition metal carbide and boride high-entropy ceramics, have been proposed for potential applications in aerospace, nuclear energy, high-speed machining and many other extreme environments, owing to their excellent physical and chemical properties including super-high hardness, low thermal conductivity, good oxidation resistance and corrosion/erosion resistance. Recently, the research of high-entropy ceramics is only focused on composition design, fabrication methods, single-phase stability and mechanical properties, but the design criterion and theoretical analysis are rarely reported. Based on the researches of high-entropy alloy, the fabrication, characterization and theoretical study of several transition metal non-oxide high-entropy ceramics are summarized, along with some related results of high-entropy film. The prospects for the future developments of high-entropy ceramics are also discussed.

Two-dimensional MXene nanosheets with vertical junction structure was employed for easy immobilization of horse radish peroxidase enzymes to fabricate the electrochemical hydrogen peroxide (H₂O₂) biosensor. The synthesized MXene nanosheets exhibited large specific area, excellent electronic conductivity and good dispersion in aqueous phase. Horse Radish Peroxidase (HRP) enzymes molecules immobilized on MXene/chitosan/GCE electrode demonstrated good electrocatalytic activity toward reduction of H₂O₂. The fabricated HRP@MXene/chitosan/GCE biosensor exhibited a wide linear range from 5 to 1650 μmol?L ^-1, a limit of detection of 0.74 μmol?L ^-1 and good operation stability. The fabricated biosensor was successfully employed for detection of trace level of H₂O₂ in both solid and liquid food.

As a new solid-state lighting source, the white light-emitting diodes (WLEDs) have a greatly promising application in the field of lighting and display. They have superior advantages of high luminous efficacy, fast response speed and long service life, etc. compared with the existing light sources (incandescent lamps, fluorescent lamps, etc.). At present the WLEDs are commonly fabricated by combination of a blue LED chip and YAG: Ce ³⁺ yellow-emitting phosphor, and combination of a ultraviolet-near ultraviolet excitation chip and red-green-blue (RGB) emitting color phosphors, compared with the above two phosphors, the single-phase phosphors containing white emission have the advantages of a higher luminous efficacy, color rendering. Meanwhile, the single-phase phosphors may effectively solve the reabsorption problem existing in RGB phosphors. There have been a large number of reports on the research of single-phase phosphors, involving a variety of material systems. According to the principle of luminescence, it can be simply divided into three groups: single ion doped system, multi-ion doped system and other systems which do not rely on rare earth ion to light. This paper reviews the research progress of single-matrix WLEDs phosphors, and points out the problems in their development, and forecasts the future development trend.

Sapphire rod with micro-tube (inner diameter: 470 μm) and sapphire plate with micro-tube (inner diameter: 160 μm) were grown by the edge-defined-film fed method (EFG). Profile curves of the small liquid menisci were investigated on the base of numerical solution of the Young-Laplace equation. By inserting Mo wires, new type of die was designed to form and sustain size of micro-tube in the volume of the crystal. Two problems were solved at the same time: 1) obtaining high quality sapphire crystal; 2) forming and sustaining necessary micro-tube sizes in the volume of the crystal. The crystal were transparent, colorless, no cracking and good XRC value of 3.8 arcmin, demonstrating the high quality of the as-grown crystal.

Graphitic-like carbon nitride (g-C₃N₄), one of the most significant two-dimensional layered materials, has attracted worldwide attention in multidisciplinary areas such as photocatalysis, energy conversion and environmental pollution management. Its derivative compounds have also attracted multifarious attention owing to the intrinsic characters of their stable physicochemical properties, low cost and environmentally friendly features. This review focus on the design of high-performance g-C₃N₄-based nanomaterials and their potential for pollutant elimination in environmental pollution cleanup. Over the past few years, signi?cant advances have been achieved to synthesize g-C₃N₄ and g-C₃N₄-based nanomaterials, and their properties have been enhanced and characterized in detail. In this review, recent developments in the synthesis and modification of g-C₃N₄-based nanomaterials are summarized. The applications in heavy metal ions adsorption from wastewaters are gathered and their underlying reaction mechanisms are discussed. Finally, a summary and outlook are also briefly illustrated.

MXenes—two-dimensional (2D) compounds generated from layered bulk materials, have attracted significant attention in energy storage fields. However, low mass loading of MXenes results in low areal capacity and impedes the practical use of MXenes electrodes. Inspired by natural basswood, an ideal architecture with natural, three-dimensionally (3D) aligned open microchannels was developed for high Ti₃C₂T_x mass loading. Compared with reported Ti₃C₂T_x electrode structure, the 3D porous carbon matrix has several advantages including low tortuosity, high conductivity and good structure stability. The Ti₃C₂T_x assembled with the wood carbon can deliver a high areal capacity of 1983 mF/cm ² at 2 mV/s with a high Ti₃C₂T_x mass loading of 17.9 mg/cm ² when used as electrode for supercapacitors. This work provides a new strategy to develop 3D porous electrodes for MXenes, which can achieve high areal capacity.

To overcome the limitation of narrow photo-absorption range and high electron-hole recombination rate of pure BiOCl, a nanocomposite of carbon quantum dots (CQDs) and BiOCl with highly efficient photocatalytic activity was fabricated. The photocatalytic decomposition of rhodamine B (RhB) showed that the CQDs/BiOCl nanocomposite displayed superior photocatalytic performance to pure BiOCl, which was about 3.4 times higher than that of the latter. The optimal loading amount of CQDs was 7.1wt%, which could completely decolorize RhB within a short period of only 2 min, while the degradation rate of RhB was only 29.5% by pure BiOCl in the same period. UV-Vis diffuse reflectance spectra (UV-Vis DRS), photoelectrochemical measurement, and radicals trapping experiments were performed to elucidate the possible mechanism for the enhanced photocatalytic activity of the CQDs/BiOCl composite. The results show that CQD can expand the visible light absorption range of BiOCl, which is beneficial for light harvesting and generation of electron-hole pairs. Moreover, CQDs has unique up-converted photoluminescence behavior, as well as photo-induced electron transfer ability, which leads to enhanced photocatalytic performance of the CQDs/BiOCl composite.

MoS₂ quantum dots (QDs) decorated NH₂-MIL-125 (MoS₂ QDs/NH₂-MIL-125) heterostructures were successfully fabricated by a facile method. XRD results exhibit that NH₂-MIL-125 and MoS₂ form crystals in the synthesis process of MoS₂ QDs/NH₂-MIL-125 heterojunctions. TEM results demonstrated clearly that the MoS₂ Quantum dots with size of about 4 nm successfully disperse on the surface of NH₂-MIL-125 plate. Compared with bulk MoS₂ and NH₂-MIL-125, the MoS₂ QDs/NH₂-MIL-125 heterostructures exhibit enhanced photocatalytic performance in degradation of methyl orange under visible light irradiation, about 5.8 and 7.4 times higher that of pure bulk MoS₂ and NH₂-MIL-125, respectively. Meanwhile, MoS₂ QDs/NH₂-MIL-125 composites exhibit good stability and reusability during cycle experiment. The excellent photocatalytic activity of MoS₂ QDs/NH₂-MIL-125 heterostructures is attributed to the formation of heterojunctions between MoS₂ QDs and NH₂-MIL-125, Tacilitating separation of the photogenerated charge carries. PL results prove that MoS₂ QDs/NH₂-MIL-125 composites own lower recombination of photogenerated electrons and holes, resulting in superior photocatalytic ability.

Ceramic matrix composites (CMCs) are promising candidates for application in aeroengine, aerospace aircraft thermal protection systems, nuclear power system, and other fields. At present, CMCs are developing from structural bearing materials to multi-functional composites. MAX phases are a group of layered ternary ceramics with excellent plastic deformation capacity, high electrical conductivity, good irradiation resistance and ablation resistance. Besides strengthening and toughening CMCs, the introducing MAX phases into CMCs can effectively improve the anti-irradiation, anti-ablation and electromagnetic interference shielding performance, meeting requirements of multi-functional CMCs. This paper reviewed the progress on MAX phases modified CMCs, design mechanism and application prospect.

Mn ²⁺ intercalation strategy to optimize the sodium storage performance of V₂C MXene was studied. The intercalated Mn ²⁺ not only enlarged the interlayer spacing of V₂C MXene but also formed a V-O-Mn covalent bond, which was beneficial to stabilize the structure of V₂C and inhibit the structural collapse caused by volume change during Na ⁺ decalation or intercalation. As a result, the intercalated V₂C MXene (V₂C@Mn) electrode showed a high specific capacity of 425 mAh·g ^-1 at the current density of 0.05 A·g ^-1, and 70% retention after 1200 cycles. This result clearly suggests that cations intercalated MXene has a great prospect in Na ⁺ storage.

Electromagnetic interference (EMI) shielding films with excellent mechanical properties are highly promising for applications in flexible devices, automotive electronics and aerospace. Inspired by the excellent mechanical properties of nacre derived from its micro/nanoscale structure, high-performance MXene/Cellulose nanocrystals (CNC) composite films were prepared by simple solution blending and followed vacuum-assisted filtration process. The presence of CNC significantly improves the mechanical properties with tensile strength increasing from 18 MPa to 57 MPa and toughness improving from 70 kJ/m ³ to 313 kJ/m ³. Meanwhile, the composite film still exhibits high electrical conductivity (up to 10 ⁴ S/m) and excellent EMI shielding efficiency (over 40 dB) with a small thickness of 8 μm.

Recently, a new type of 2D transition metal carbides or nitrides (MXene) has attracted wide attention due to its large specific surface area, good hydrophilicity, metallic conductivity and other physical and chemical properties. 2D Ti₃C₂T_x MXene was obtained by etching Al layer of Ti₃AlC₂ with LiF and HCl and then mechanically delaminated. And the monolayer Ti₃C₂T_x nanosheets with lateral dimension of 625 and 2562 nm can be prepared by changing the intensity and way of mechanically delamination, as well as the centrifugation rate and time. Then their morphology, structure, composition, and electrochemical performance of Ti₃C₂T_x were studied. The results showed that the specific capacitance of Ti₃C₂T_x with smaller lateral size (<1 μm) can reach 561.9 F/g, higher than that of reported graphene, carbon tube and MnO₂ in the repotted literatures. And the Ti₃C₂T_x electrode still remained 96% of the initial specific capacitance after 10 ⁴ testing cycles.

Bacterial cellulose (BC), an eco-friendly bio-product obtained from fermentation of various microorganism, consisting of the interconnected networks structure attracted widespread interest due to its unique physical properties, including the large specific surface area, remarkable mechanical strength, high water-holding ability, good chemical stability, and environmental benign material. These advantages enable BC to be applied to fabricate the highly versatile three-dimensional (3D) carbon nanomaterials, and tunable flexible scaffold to support other multifunctional materials. In this review, the production process of various carbon nanofibrous composites based on BC, such as carbon nanofiber (CNF), doped CNF, CNF/metal oxide and CNF/conducting polymer, is presented. Their emerging applications in supercapacitors are illustrated, in particularly, the design of hybrid bendable electrodes based on BC substrate for flexible supercapacitor is highlighted. The challenges and opportunities in this fascinating area of designing functional nanomaterials and flexible electrode from BC for various energy storage are addressed. Moreover, the perspectives are given for the future development, including several significant kinds of study for applications in the rechargeable battery.

Persistent organic pollutants can be effectively removed by photocatalytic oxidation, which reveals potential application prospects in the field of wastewater purification. Binary reduced graphene oxide and graphitic carbon nitride (RGO/g-C₃N₄) visible-light photocatalyst was successfully fabricated by the freeze drying assisted thermal polymerization method with urea and dicyandiamide as raw materials, respectively. The morphologies, structures and optical properties were characterized by various techniques. It was found that g-C₃N₄ and RGO nanostructures formed an intimate contact across the heterojunction interface. The photodegradation performances of catalysts were evaluated by removing bisphenol A (BPA) with the activation of persulfate (PS). The results indicated that the photocatalytic activities of photocatalysts were enhanced with the addition of PS as an oxidant and electron acceptor under visible light irradiation (λ>420 nm). Moreover, BPA was almost completely removed by RGO/g-C₃N₄ prepared with urea as raw material in 40 min. After five recovery tests, the removal efficiency of BPA for the catalyst was up to 80% within 40 min under visible light irradiation, which exhibited superior stability.

Phase diagrams are used as an indicator to estimate the thermodynamic stabilities of the novel MAX phases (Ti₃AuC₂, Ti₃IrC₂, Ti₃ZnC₂, Ti₂ZnC). The phase diagrams of the Ti-Au-C, Ti-Ir-C, and Ti-Zn-C systems were obtained using the CALPHAD (Calculation of Phase Diagrams) approach coupled with ab initio calculations. The calculated results confirmed thermodynamic stabilities of the synthesized Ti₃AuC₂, Ti₃IrC₂, Ti₃ZnC₂, and Ti₂ZnC MAX phases, which is in great agreement with the experiment information. The present work shows a systematic method to calculate the thermodynamic stability of the novel MAX phases, which can be used as guidance to synthesize more undiscovered MAX phases.

Two-dimensional materials have attracted broad interest because of their wide variety of properties. They can be used as photocatalysts and electrocatalysts due to their extremely high specific surface area, and have great potential application in the field of environment and renewable energy. This review focuses on the structure and properties of common two-dimensional materials such as 2D carbides and nitrides (MXenes), g-C₃N₄ and black phosphorus (BP). Furthermore, the latest research on the modification of two-dimensional materials in the area of photocatalysis and electrocatalysis are discussed and commented. Finally, research prospects for two-dimensional materials in the future are predicted.

Membrane-based gas separation is one of the critical technologies in filtration and separation industry, since it is more efficient, energy-saving and environmentally friendly compared with traditional separation technologies. Novel inorganic two-dimensional materials (2DMs) for gas separation are expected to achieve both high selectivity and high permeability, breaking through the trade-off between selectivity and permeability of commercial polymer membranes. This review begins with a brief explanation of gas separation mechanisms for membranes. Afterwards, special attention will be given to the recent advances in novel inorganic 2DMs including graphene and their derivatives, TMDs and MXene, about their design, fabrication and application in gas separation. The gas separation characteristics of different materials, their challenges and directions for future research are summarized. Moreover, the application of other novel inorganic 2DMs, such as LDH, h-BN and mica nanosheets in gas separation technology is also discussed. Finally, the perspectives and challenges for future research of novel inorganic 2DMs in gas separation field are outlined.

Cu₂S shows excellent thermoelectric properties as a material with phonon liquid-electron crystal characteristics. However, traditional preparation methods are cumbersome and difficult to afford bulk Cu₂S with uniform composition, high density and excellent thermoelectric properties. In this study, a novel method named Pulsed Electric Current Sintering was introduced to synthesize and sinter Cu₂S materials in one step consuming only 30 s. The synthesis of Cu₂S under intense pulsed electric field includes three steps. A small amount of CuS and Cu₂S forms in the first step; most of Cu₂S and part of Cu_1.96S are produced in the second step; finally, the remained Cu_1.96S and Cu react to form completely pure Cu₂S. The Cu₂S bulk obtained by this method is a dense bulk with homogeneous composition, and contained abundant multi-scale microstructures. The thermoelectric performance is optimized by regulation of Cu-deficient Cu_2-xS. The maximum ZT of Cu_1.97S bulk at 873 K is 0.72, which is 49% higher than that of the pristine sample.

Metal organic frameworks (MOFs) materials have received extensive attention in capture and separation of CO₂. Herein, molecular dynamic simulation (MD) and grand canonical Monte Carlo (GCMC) simulation were used to investigate the process of negative gas adsorption to DUT-49, an MOF, and the effect of structural transition on the CO₂/N₂ adsorption and separation behavior. Results showed that DUT-49 underwent stable structural deformation at 20-60 MPa, with a transition between open pore (DUT-49-op) and closed pore (DUT-49-cp). Its adsorption capacity decreased with the increase of temperature. DUT-49-cp owned a contractive framework, exhibiting a considerably decreasing adsorption capacity due to reduction of effective adsorption sites. In addition, its selectivity decreased significantly compared with that of DUT-49-op, and decreased with increase of temperature, which is not conducive to gas separation. The present study provides a scientific basis for the development of adsorbent materials.

During charge and discharge of lithium-ion battery, the concentration gradient produced by lithium- ion diffusion process and deformation caused by lithiation expansion of the active material result in diffusion-induced stress. Excessive diffusion-induced stress can cause various mechanical failure modes such as cracking of active particles, separation between active particles, fracture of active layers, and delamination between active layers and current collectors, which eventually leads to a series of failure phenomena such as capacity attenuation, impedance rise and cycle life loss of the battery. Therefore, the diffusion-induced stress and the derived failure mechanism of lithium-ion battery become one of the research hotspots in the field of lithium-ion batteries, which has important theoretical and practical value. In this paper, research progress of the failure mechanism of lithium-ion battery caused by diffusion-induced stress in recent years is reviewed from different levels of the active particle, the active electrode, the half-cell, the cell unit, and the cell. The generation mechanism and research methods of diffusion-induced stress are introduced. The influence of diffusion-induced stress on the mechanical and electrochemical properties of the battery is analyzed, and the influencing factors of the diffusion-induced stress are summarized. Finally, the future research directions and development trends are prospected.

The third generation SiC fibers have near-stoichiometric composition and polycrystallinity with high density. Compared with the first and second generations, they have obvious improvements in heat-resistance, creep-resistance and radiation-resistance. Accordingly, they have more advantages and broader prospects in engineering applications, especially in the nuclear field. In this paper, the fabrication and performance characteristics of the third generation SiC fibers are introduced and compared. The applications of the third generation SiC fibers in the field of nuclear energy are reviewed, and the development prospects are prospected.

Solid-state cooling technology based on the electrocaloric (EC) effect is attracting increasing attention as an important alternative for traditional cooling systems because of its advantages of high efficiency, environmental friendliness, light weight, low cost, and easy miniaturization. Ferroelectric materials are suitable candidates for EC refrigeration due to their large polarization and entropy change through applying or removing an external electric field. Recently, study on the EC effect of lead-free bulk ceramics has become one of hot topics on ferroelectric community due to the requirements of sustainable development. In this review, we firstly introduce the significant history events in EC research and the basic principles of EC refrigeration. Then, design strategy for achieving a large EC temperature change near room temperature and a wide using range is summarized. Subsequently, we systematically review the research status of EC effect in BaTiO₃-based, Bi_0.5Na_0.5TiO₃-based and K_0.5Na_0.5NbO₃-based lead-free bulk ceramics and discuss their advantages as well as challenges. Finally, we propose some prospects for the future work on EC effect in lead-free bulk ceramics.

In recent years, the development of new energy vehicles industry is accelerating. Lithium nickel cobalt manganese/aluminum oxide ternary cathode materials (NCM/NCA), especially with the nickel content ≥50%, has aroused great interest in both academia and industry. This is mainly due to the fact that the aggregative parameters of performance and cost of NCM/NCA are superior to those of traditional cathode materials, such as LiCoO₂ and LiFePO₄. However, the application of NCM/NCA is affected by a number of drawbacks, including poor safety and insufficient cycle stability and so on, which are mainly attributed to its crystal and surface structure. Researchers have carried out various efforts to solve these problems and further improve the performance of NCM/NCA. Some remarkable results have been achieved in the past few years. In this review, the latest research progress on coating and doping of Ni-rich ternary cathode materials is summarized from the view on the mechanism of structural and electrochemical improvement of NCM/NCA. Finally, the perspective for the development of NCM/NCA cathode materials is also prospected.

Lanthanum-substituted La_xSr_2-3x/2Fe_1.5Ni_0.1Mo_0.4O_6-δ (La_xSFNM, x=0, 0.1, 0.2, 0.3, 0.4) oxides were synthesized by the solid-state reaction method, and investigated as potential anodes for Solid Oxide Fuel Cells(SOFC). X-ray diffraction patterns of as-synthesized powders confirm the formation of the cubic perovskite structure. Reduction in H₂ promotes the segregation of nano-scale metallic Fe-Ni alloy particles on the grain surfaces. Scanning electron microscopy observations indicate that increasing La ³⁺ dopants results in a decrease in the density of the exsolved nanoparticulates. Based upon impedance measurements on symmetrical fuel cells, the anode polarization resistance decreases with the La ³⁺ dopant increasing, and attains a minimal value of 0.16 W?cm ² for La_0.3SFNM at 750 ℃, followed by a slight increase to 0.17 W?cm ² for La_0.4SFNM. The highest catalytic activity of La_0.3SFNM toward electro- oxidation of hydrogen fuels could be ascribed to the synergy between the exsolved Fe-Ni alloy nanoparticulates and the supporting La_xSFNM oxides. Thin La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) electrolyte fuel cells with La_0.3SFNM anodes and SmBa_0.5Sr_0.5Co₂O₆ cathodes exhibit the highest power densities, e.g., 1.26, 0.90 and 0.52 W?cm ^-2 at 750, 650 and 550 ℃, respectively. These results demonstrate La_0.3SFNM oxide as a promising high performance SOFC anode.

Extrusion stress due to phase change of the NiS, internal stress due to CTE mismatch between the NiS and glass, and local concentrated stress around the NiS due to synergistic effects above were quantitatively calculated based on equal strength theory and the deformation coordination relation between NiS and glass in this work. The effects of NiS particle diameter, local strength of glass and ambient temperature on spontaneous breakage of tempered glass were analyzed. The critical diameter of NiS particles was determined as well. The results show that the fundamental reason for spontaneous breakage of tempered glass is the circumferential concentrated stress (tensile stress) near the NiS particle. There exists non-linear relations between circumferential stress and NiS particle diameter of which the circumferential stress decreases rapidly with the decrease of NiS particle diameter when it is less than 0.2 mm, but circumferential stress increases moderately when it is greater than 0.5 mm. The critical diameter of NiS particle which causes the spontaneous breakage of tempered glass decreases with the increase of surface stress in the tempered glass. It is difficult to induce spontaneous breakage of tempered glass when the diameter of NiS particle is less than 0.1 mm. The circumferential stress increases linearly with the increase of ambient temperature, and the stress increases slightly faster for the NiS with larger diameter.

It is a worldwide challenge to simultaneously improve the strength and damage tolerance of ceramics, which is a core issue in the development of ceramics and a goal pursued by materials scientists. While the pre-stressed design has been widely used to improve the strength of concrete and glass for over a century, a little progress has been made for ceramic materials. In this paper, the research progresses of ceramic reinforcement are summarized, and a new pre-stressed design and model of high strength and high damage tolerance composite ceramics are proposed. The novel design focuses on the generation of residual compressive stresses on the surface of ceramic components to inhibit crack initiation and growth, and offset the external tensile stress, which can be applied to different fields such as structural ceramics, architectural ceramics, domestic ceramics and so on. This simple and economical technique with no limitation of size and shape in ceramic components has great application prospects.

As smart electronic products are increasingly applied in our daily life, there is not only an increasing demand for high-performance photovoltaic power generation devices, but also strong need for in-situ energy storage functions in these devices. The integration of energy generating components and energy storage components into one device has become an attractive challenging technology. The basic idea is that by integration design and engineering the assembly of the photoelectric conversion layer and the energy storage layer into one in-situ energy conversion and storage system could not only offer multiple functions, such as self-powered ability, weak light buffer and portability, but reduce sunlight fluctuation effect on energy output. This review summarizes the research progress in novel in-situ integrative photovoltaic-storage tandem cells, classified by silicon solar cell, sensitized solar cell and perovskite solar cell. Evaluation of methodology, operational principle, construction feature, and performance parameter are also discussed and critically reviewed, and the further development of in-situ integrative photovoltaic-storage tandem cell is also prospected.

Phase diagrams, also known as equilibrium phase diagrams, serve as a road map for materials design. However, preparation process of coatings (such as Physical Vapor Deposition, PVD) is generally far from equilibrium and results in metastable phases. Thus, the CALPHAD (Calculation of Phase Diagrams) approach faces a challenge in calculating the metastable phase diagrams for PVD coating materials. Here we summarized the development of the modeling methodology for the metastable phase diagrams, where the model with critical surface diffusion distance established in recent years were highlighted. The CALPHAD approach, first-principles calculations coupled with high-throughput magnetron sputtering experiments were used to model the atomic surface diffusion, while only one key combinatorial experiment was performed to obtain the basic data for the computation, and the calculated metastable phase diagrams were confirmed by further experiments. Therefore, the database of the stable and metastable phase diagrams can be established, which will be used to guide the design of the ceramic coating materials by the relationship of composition, processing, microstructure, and performance. This model can also help to achieve the goal to shorten the time and reduce the costs of materials research and development.

Carrier SiO₂ was synthesized through Sol-Gel method, and the photocatalytic antibacterial material of TiO₂@SiO₂ composite was prepared by hydrolysis method. The synthesized composites were characterized. The photocatalytic properties of the composites were investigated by degrading methyl orange with UVA irradiation. After 3 h irradiation, all of composites with different amount of titanium doping can reach 99.9%. And the optimal catalytic efficiency of the composite is obtained when the titanium doping ratio (molar ratio) is 0.58. Antibacterial effect of composites on Escherichia coli, measured by plate coating method, shows that the antibacterial properties are improved with the increase of titanium content, which reach up to 92% under UVA irradiation. Moreover, the composites also exhibit favourable antibacterial properties under visible irradiation. Though fluorescence detection of bacterium, it is proved that the reactive oxygen species (ROS) produced by the composites migrate into the cells and cause the oxidative damage of the cells, which is a significant basis for the antibacterial mechanism of photocatalytic materials.

Carbon capture and storage (CCS) is a promising strategy for reduction of CO₂ emissions. Herein, CO₂/N₂ adsorption and separation in three SIFSIX-X-Cu (arrayed via SiF₆ ^2- with Cu metal center, X = 2, 3, O) hybrid ultramicroporous materials at 298 K within 0-5 kPa were investigated by using grand canonical Monte Carlo (GCMC) simulation. Results showed that, in contrast to SIFSIX-2-Cu, CO₂ adsorption in SIFSIX-3-Cu and SIFSIX-O-Cu reached saturation at 0.5 kPa and their CO₂ adsorption capacity were 2.70 and 2.39 mmol·g ^-1 at 1 kPa, respectively. The CO₂ adsorption capacity in CO₂/N₂ mixture barely decreased. SIFSIX-3-Cu and SIFSIX-O-Cu owned close pore sizes to CO₂ dynamics diameter, thereby exhibiting high CO₂ affinity with adsorption heat of 59 and 66 kJ·mol ^-1, respectively. Density functional theory (DFT) analyses showed only one CO₂ molecule could be adsorbed in each hole and located at the center of SIFSIX-3-Cu and SIFSIX-O-Cu. Our results provide a theoretical guidance for developing ultramicroporous materials in adsorption and separation of CO₂ at low pressure.

Remineralization of early enamel caries lesions plays a crucial role in prevention and restoration of dental caries. Based on the crucial amino acids contained in enamel matrix, amino acids /hydroxyapatite (AA/HAP) composite was synthesized in the presence of 10 mmol/L glycine, 10 mmol/L L-serine and 5 mmol/L L-aspartic acid. The physical, chemical and biological properties of the composite were characterized. And its remineralization effect on acid-etched bovine enamel was evaluated. Under the inhibition properties of amino acids, the composite has lower crystallinity and higher biocompatibility compared to the hydroxyapatite (HAP) without amino acids. In vitro remineralization of acid-etched bovine enamel using AA/HAP was conducted in artificial saliva. After remineralization, the surface and cross-section morphology, the components, and the mechanical property of bovine enamel samples were characterized, respectively. The results showed that the AA/HAP could induce the restoration of both surface and subsurface enamel lesions. The amino acids released from the composite could adsorb on the organic matrix residues and induce the formation of parallel arranged HAP crystals, eventually formed significant surface microhardness (SMH) recovering.

Mo₂Ga₂C, a double-A-layer MAX, is reported to be films or powders. This paper researched the sintering properties of M₂Ga₂C powders to make dense bulk samples by vacuum hot pressing. It was found that 750 ℃ was a suitable sintering temperature, while higher temperature (850 ℃) resulted in decomposition of Mo₂Ga₂C yielding to main product of Mo₂C. During sintering process at 750 ℃, its grain size did not increase obviously with sintering time, meanwhile the size of pores decreased markedly and the relative density increased significantly with the increasing sintering time. Additionally, the hot-pressed samples had obvious texture. Due to layering, some grains changed their orientations during sintering, of which most of the (00l) planes in the hot-pressed samples preferred to be perpendicular to the direction of hot press. Almost fully densed Mo₂Ga₂C bulk (relative density: 98.8%) was obtained by hot pressing at 750 ℃ for 8 h. This advantage of the method suggested that it can serve as a promising preparation for Mo₂Ga₂C, a double-A-Layer MAX.