Nanoporous materials have attracted great attention in the fields of adsorption and membrane separation due to their remarkable nanoscale spatial effects. As an extension of inorganic porous materials, metal organic framework (MOF) has been widely used in gas-phase storage and separation, liquid-phase adsorption separation and catalytic reaction due to its large specific surface area, high porosity and adjustable pore structure. In this paper, the types of MOF are classified, and the synthesis methods and particle size control mechanism of MOF materials were compared. Among them, the advantages of solvothermal synthesis were emphatically introduced. At the same time, the problems and limitations of MOF materials in adsorption separation research were summarized systematically, and the advanced preparation technology of composite membrane based on MOF materials was prospected; the application of MOF in gas storage separation, liquid adsorption separation and membrane separation was summarized. Finally, for the preparation of composite membrane, the idea of improving the compatibility of MOF material and organic membrane by changing the synthesis method of MOF was proposed.

Solid phase additive manufacturing based on friction stir is a new technology for manufacturing of large lightweight alloy components, which has become one of the hot research topics in advanced manufacturing field at home and abroad.The research status of metal solid phase additive manufacturing technology based on friction stir and related process mechanism were analyzed and summarized. The solid phase additive manufacturing technology based on friction stir can be divided into three categories.One is friction stir additive manufacturing(FSAM), which is based on the principle of friction stir lap welding, the plates are stacked layer by layer. Another is additive friction stir deposition(AFSD) technology, which usually uses a hollow tool to conduct AFSD by additive powder or wire through the hollow.The third one is friction surfacing deposition additive manufacturing (FSD-AM) technology, which is based on the principle of friction surfacing by using a rotating consumable bar to deposit materials to form the designed components. The research and application status of solid phase additive manufacturing technology of metal materials based on friction stir were analyzed, and the characteristics, advantages and disadvantages of three kinds of solid phase additive manufacturing technology based on friction stir were compared.Finally, the future research direction of solid phase additive manufacturing technology based on friction stir was proposed, including revealing their process mechanism, integrated controlling of the formation and property of the AM components, modifying the process assisted with second energy, application of new materials and optimization with artificial intelligence, etc.

As a two-dimensional(2D) building block of new materials, graphene has received widespread attention due to its exceptional thermal properties. The thermal properties and recent advances on graphene-based material were reviewed. The intrinsic thermal conductivity of graphene and the effect of layers, defects and edge were briefly introduced. The resent research progress in graphene fiber as thermal conductivity material was analyzed and discussed. A variety of graphene films (graphene film, graphene hybrid film, graphene/polymer composite film) were grouped by category and the influencing factors of the thermal conductivity were reviewed. The structure, thermal conductivity property and current researches of 3D graphene (graphene with random orientation in the polymer matrix, graphene with specific orientation in the polymer matrix) were summarized. Finally, the challenges and prospects of graphene-based materials were also pointed out, especially inhigh power, highly integrated systems such as LED lighting and smart phones, graphene based thermal conductivity materials have a good development prospect.

With the increasing demand for lithium-ion batteries, lithium-ion batteries with high energy density and high power density have become one of the research hotspots. Material modification and new material development can effectively increase the energy density of lithium-ion batteries. In addition, the microstructure parameters of the electrode such as porosity, pore size and distribution, tortuosity and electrode composition distribution are also factors that determine the performance of the electrode and battery. Improving the performance of high specific energy batteries by optimizing the electrode structure design has gradually become the focus of attention. The research progress of porous electrode structure design optimization for lithium ion batteries was reviewed in this article, the design factors and preparation methods of porous electrode structure were summarized. Then the future development of electrode structure design optimization and the promotion of novel preparation technologies for large-scale application in the field of high specific energy lithium ion batteries were prospected in the field of high specific energy lithium ion batteries.

Lithium metal batteries have been considered as one of the most promising high-energy-density energy storage devices, however, the low Coulombic efficiency and uncontrolled dendrite growth seriously hinder their commercialization. In lithium metal batteries, the electrolytes would directly participate in the formation of solid electrolyte interface (SEI), which play important roles in affecting the lithium metal anode Coulombic efficiency and inhibiting the growth of lithium dendrites.In the traditional LiPF₆ based ester electrolyte, lithium metal anode exhibits low Coulomb efficiency and serious lithium dendrites.In recent years, significant improvement has been achieved for the protection of lithium anode through manipulating the electrolyte additive, solvents, lithium salt and lithium salt concentration, etc. For examples, ether solvent presenting better compatibility with lithium metal was selected to reduce the side reactivity of electrolyte with lithium metal; varieties of additives were adopted to suppress the formation of lithium dendrites; high concentration electrolytes were employed to form stable SEI.In this paper, the growth principles of lithium dendrites, the research status of electrolytes chemistries for protection of lithium metal anode by means of solvents, lithium salts, additives and high concentration electrolytes strategies were reviewed and the advantages and limitations of various approaches were summarized.New insights on the development of electrolytes chemistries were also put forward to stimulate new strategies to face the subsequent challenges of lithium-metal batteries.

Auxetic metamaterials and structures have excellent mechanical properties such as shear resistance, impact resistance, fracture resistance, energy absorption and vibration isolation, permeability variability, synclastic curvature in bending, etc. Auxetic metamaterials have broad application prospects in the fields of aerospace, navigation, mechanical automation, biomedicine, national defense and military and textile industry. Based on the deformation mechanism of auxetic metamaterials and structure, the physical models of re-entrant mechanism, rotating rigid mechanism, chiral/antichiral mechanism, fibril/nodule mechanism, miura-folded mechanism, buckling-induced mechanism, helical auxetic yarn structure were reviewed. These models can be widely applied in various engineering applications such as light laminated plates, fluid transportation and yarn to improve their properties. Finally, prospects to the upcoming challenges and progress trends of auxetic metamaterials and structures are made.It is pointed out that the application of negative Poisson's ratio effect can help compensate the change of volume and area under the deformation of uniaxial loading. Then the shock resistance of turbine blade, antenna and car suction box can be improved. As a result, this review can provide benefits for the development of auxetic metamaterials.

Based on different high-entropy alloys (HEAs) systems, the latest research progress in additive manufactured high-entropy alloys was reviewed. The rapid solidification microstructure, segregation and precipitation behaviors of high-entropy alloys fabricated by additive manufacturing with different compositions were described. Especially, the analysis was focused on the mechanical properties, deformation and strengthening mechanisms. It was pointed out that the appropriate additive manufacturing process should be selected for different high-entropy alloy systems, and the influencing factors of forming quality need to be further studied. Finally, it was proposed that high-entropy alloys with both excellent strength and high plasticity can be developed and prepared by additive manufacturing technology.

Owing to the excellent biocompatibility and corrosion resistance of titanium and its alloys in the biological environments, they are one of the best materials in the medical implant applications. Moreover, it has a lower elastic modulus (comparable to bone) than traditional metal implant materials which is an influential property due to the stress-shielding effect. There are some requirements for implant materials according to their clinical use and the periphery tissues. Hence, some factors should be considered, such as metal degradation, toxicity issues, surface characteristics, biocompatibility, and fusion with bone. Considering the above-mentioned information, titanium material design with superior performance to meet the essential clinical needs is an important challenge and attracts much attention from the academicians in the biomaterial field. This paper discusses the structural and performance characteristics of medical titanium alloys and the current research status in the direction of orthopedic applications. Furthermore, in future research, through changing the elemental composition, increasing the surface modification, and optimizing the production process, titanium alloy materials could have the excellent comprehensive performance to serve human beings better.

TiO₂ nanomaterials have many disadvantages, including high photo-generated electron-hole recombination rate, low electron mobility, poor electrical conductivity and low reversible capacity, which have restricted application in the fields of photocatalysis and electrochemistry. MXene (M_n+1X_nT_x), a new type of two-dimensional transition metal carbides, nitrides, or carbonitrides, has a unique two-dimensional layer structure, excellent electrical conductivity, and high carrier mobility. By introducing MXene into TiO₂ nanomaterials to construct the TiO₂/MXene nanocomposites, the synergistic effect of MXene and TiO₂ can further improve photocatalysis and electrochemistry properties. From the perspective of TiO₂ nanomaterials, the latest research progress on the controllable preparation, structural properties, applications in photocatalysis and electrochemistry of zero-dimensional, one-dimensional, and two-dimensional TiO₂ with MXene nanocomposites were reviewed. In particular, the construction mechanism of namocomposites and the enhancement mechanism of photocatalysis and electrochemistry properties of TiO₂ by MXene were emphasized. The shortcomings of the existing research on preparation of TiO₂/MXene composites and its applications in photocatalysis and electrochemistry were analyzed.Furthermore, the future research directions of TiO₂/MXene composites from the aspects of optimizing the preparation process, improving the properties and exploring the property enhancement mechanism were also prospected.

Electromagnetic interference problems have become an increasing issue with the rapid development of wireless information technologies, which has attracted global attention. The key solution to this challenge is to develop materials that can absorb electromagnetic waves. The ideal absorbing material should be a structural material integrating load bearing, heat protection and strong absorption. The carbon-based, ceramic-based composites and their electromagnetic absorption properties in recent years were summarized in this review. The ultimate goal of these absorbers is to achieve broader effective absorption frequency bandwidth at a thin coating thickness. The synthesis methods, structures and electromagnetic wave loss mechanism of several typical and well-received composites were introduced. The superiorities, research status and main problems of absorbing materials were described. Based on these progresses, the potential development direction of absorbing materials in the future was predicted.

With the success of bringing back lunar samples, Mars exploration and space station construction, new requirements for high performance materials were put forward with the devel-opment of China's new space missions. Based on the analysis of the current situation and trend of China's aerospace development, some demands for high performance materials such as lightweight high performance structural materials, lightweight high efficiency thermal protection materials, structural & functional integration materials, new multifunctional composite protective materials, extreme temperature resistant functional materials, intelligent materials, high performance spacesuit materials, functional gradient materials, meta-materials, 3D printing materials and 4D printing materials were analyzed. Finally, nanotechnology, material genetic engineering and other new technologies were put forward to incorporate the space environment into the whole process of aerospace materials development and to further carry out the research and development of aerospace materials.

With the improvement of alloy manufacturing level and the complexity of performance requirements, high-entropy alloys (HEAs) have gradually attracted great attention.At present, the research in the field of material processing mainly focuses on brazing and surface engineering.In the field of brazing, HEAs can be used as filler material for brazing at high temperature and low temperature, the empirical parameters related to high entropy were summarized. The application of the simulation and calculation methods such as first-principle method and calculation of phase diagram were described in the field of HEAs design for filler metals development. The latest research progress of HEAs fillers for brazing of nickel-based superalloys and dissimilar ceramics-metals, as well as low temperature packaging was introduced. The influence of welding process parameters on microstructure and properties of HEAs brazing joints was also analysed.In the field of surface engineering, the application direction and preparation methods of HEAs in film/coating were discussed. The research progress in high-temperature protective coating, hard protective layer and other application directions was summarized. At the same time, the problems existing in the research and application of HEAs in the fields of brazing and surface engineering were summarized. The future trends were put forward in order to decrease the melting temperature of HEAs filler, improve high temperature mechanical properties of welds, and develop the eutectic HEAs filler/coating.

Lithium metal has a low redox potential (-3.04 V vs standard hydrogen electrode) and high specific capacity (3860 mAh/g), making it an ideal anode material for lithium secondary batteries. The solid-state lithium battery assembled by metal lithium negative electrode/solid electrolyte/lithium-inserted positive electrode is expected to become the power source of related technology industries such as aerospace, robotics, high-end electronics and electric vehicles in the future. However, during the charging and discharging process, due to the uneven deposition and dissolution of lithium, a large number of dendrites are produced on the contact surface between lithium and the electrolyte, and they continue to grow along the direction of the electrolyte, eventually causing the internal short circuit and failure of the battery. The use of a solid electrolyte with a higher Young's modulus can block the growth of lithium dendrites to a large extent, but still cannot meet the requirements of battery long-term cycling and safety. In addition, metal lithium is in solid-solid contact with the solid electrolyte surface, causing problems such as high electrical resistance across the interface and interfacial reaction between metal lithium and solid electrolyte, which severely hinders the development and use of solid lithium metal batteries. The strategies for inhibiting the growth of lithium dendrites and improving the compatibility of solid-solid interface in metal lithium batteries based on solid electrolytes in recent years were reviewed in this article, and prospects for future development on the interface engineering of Li metal and solid-state electrolytes were prospected.

As one of important candidates for advanced aerocraft engine hot components, SiC/SiC composites would undergo oxidative and corrosive damage when subjected to high temperature combustion environment. Oxidation behavior of SiC/SiC composites at 1100-1300 ℃ in air was investigated in the present work, to clarify the oxidative and corrosive behavior of the composites. The oxidation kinetics curves were obtained. The morphology and composition evolution of the oxidized materials were analyzed by SEM, XPS and XRD. The results show that the oxidation kinetics of SiC/SiC composites at 1100-1300 ℃ follow the parabolic law and the oxides on the surface mainly consist of silica. Slight oxidation occurs at 1100 ℃. The oxidation rate increases with increasing temperature. The oxidation process is mainly concentrated in the BN interface phase and the pores of the matrix. The bending strength of the composite decreases with the oxidation extent.

Wire arc additive manufacturing (WAAM) attracts much attention due to its unique feature of rapid near net shape forming without die. It has the potential to become an advanced manufacturing technology that can break the bottleneck of alloy development and industrial application for aluminum materials. Wire arc additive manufacturing technology originates from traditional arc welding, and both of them use high-energy arc as heat source and metal wires as raw material. The WAAM technology and equipment development, the solidification and solid state phase transformation performance, microstructures, metallurgical defects as well as mechanical property of aluminum alloys were reviewed. The technique prospects of hot wire and multi-wire additive manufacturing, the unique fabrication manner and the exclusive phase transformation microstructure were discussed. The WAAM-specialized approaches to address the issues of poor manufacturing accuracy, serious porosity and cracking, and unsatisfied mechanical property, including fabrication system development, metallurgical defect controlling, alloy composition and microstructure design and heat treatment optimization were proposed. Such proposals are expected to facilitate the rapid development of high-end, customized and distinguished aluminum alloys via WAAM.

In recent years, graphene-based aerogels (GAs) have been extensively studied owing to the excellent characteristics of low density, high specific surface area and porous structure, which show great potential in many applications. The disadvantages of traditional bulk graphene-based aerogels, for instance, strong device-dependence, large size and poor scalable production, limit their practical application and development. Meanwhile, conventional preparation techniques ignore the requirements of materials shape and size for specific application scenarios. As a new aerogels display form with novel structure, graphene-based aerogel microspheres (GAMs) not only have various advantages of GAs but possess properties of flexible and controllable size and scalable production, which tremendously enrich the application scenarios of GAMs.The fabrication methods and structure of GAMs, as well as the application fields of water pollution treatment, electromagnetic wave absorption and electrocatalysis were elaborated in this review.Meanwhile, the internal mechanism of GAS during molding assembly process was also pointed out.

Hypersonic flight technology is an important direction in the development of aerospace field and plays an important role in national defense security. The thermal protection materials and structures are the key to the safe service of hypersonic vehicles in extreme environments. On one hand, the thermal protection materials and structures must be able to withstand the harsh aerodynamic thermal environment, and on the other hand, they also must reduce its mass to increase the vehicle payload. Therefore, it is necessary to develop thermal protection structures that can combine high temperature resistance, light weight, and load-bearing characteristics at the same time. The manufacturing methods of lightweight C/SiC ceramic matrix composite structures were firstly introduced in this review, then the research on the room temperature and high temperature mechanical behavior, heat transfer mechanism and behavior of the lightweight C/SiC ceramic matrix composite structures were summarized. At last, integrated thermal protection structures with high temperature resistance and lightweight load-bearing were reviewed based on the lightweight C/SiC ceramic matrix composite structures. Finally, the future challenges of the lightweight ceramic matrix composite structures towards thermal protection application were also forecasted in four aspects: new design theory and method, new manufacturing technology, service characteristics and multi-functional integrated design and realization. This review provides some guidance for the research and development of novel thermal protection structures for the next generation hypersonic flight.

The lightweight of vehicles is one of the important means to solve the energy crisis and environmental problems, which has been paid great attention by scholars at home and abroad.Carbon fiber-reinforced polymer (CFRP) composites and light alloys such as aluminum and magnesium alloys have a series of excellent mechanical properties and processing performance, representing lightweight materials with great application prospects. It has become a hot research topic to realize the effective joining between the CFRP and aluminum/magnesium alloys which are the promising lightweight materials. However, due to the significant differences in physical and chemical properties between these dissimilar materials, the mixed application of a variety of lightweight materials in the production process is still facing great challenges.The research progress, advantages and disadvantages, and development trend of bonding, mechanical fastening, friction stir welding and its variants were summarized and analyzed. The micro morphology of joints obtained under different bonding methods was investigated. Three mechanisms of friction stir joining between CFRP and aluminum/magnesium light alloys were preliminarily summarized through investigating the micro morphology of joints, including macro anchoring, micro mechanical chimerism and chemical bonding. Finally, based on the above joining mechanism, it is pointed out that the key to further improving the performance of hybrid joints is to increase the surface roughness of the base metal, increase the area of the molten polymer and adopt the hybrid joining techniques.

Carbon/Carbon(C/C) composites are widely used in aerospace industry due to their diverse advantages such as low density, reliable thermal shock resistance and excellent mechanical properties at elevated temperatures. However, their awful oxidation resistance, especially at higher temperatures, has greatly limited their further applications. Ultra-high temperature ceramics(UHTCs) are ceramics whose melting points are higher than 3000 ℃. Some advanced performances like high strength, high hardness and outstanding thermal stabilities have given the UHTCs huge potential in ultra-high temperature applications. Using UHTCs to modify the matrix of C/C composites is a commonly applied method to improve the oxidation resistance of the C/C composites. There are numerous methods to fabricate UHTCs modified C/C composites(C/C-UHTCs), yet none of them could assure low cost, high efficiency and uniform bulk density simultaneously. Compared to C/C composites, C/C-UHTCs possess better performances both in anti-oxidation ablation and mechanical properties. But, the long-term(over 120 s) anti-oxidation ablation properties and anti-oxidation ablation properties of prototype structures are waiting to be improved to meet the updated requirements of modern sharp-edged aerospace vehicles. Meanwhile, reducing the brittleness of the modified composites and improving the reliability of the structure should be considered in order to avoid the hazard brittle fracture of the composites. In order to provide references to future studies, the state of the arts of the C/C-UHTCs were reviewed from four perspectives, which were manufacture processes, microstructure morphologies, anti-oxidation ablation properties and mechanical performances. Moreover, the future research tendency of this kind of composites was also predicted in this work.

Compared with traditional lithium-ion batteries, all-solid-state lithium-metal batteries (ASS LMBs) have attracted much attention due to their high safety and high energy density. However, the solid-solid contact of electrodes with solid electrolyte brings large interfacial impedance. Besides, the active lithium metal reacts with most solid electrolytes, leading to unstable interface. So interfacial problem has been one of the key issues to limit the development of ASS LMBs. Solid composite electrolytes with the advantages of inorganic solid electrolytes and organic solid electrolytes, have higher ionic conductivity and certain mechanical strength, showing excellent promising in the light of practical application. The research progress on interface amelioration of solid composite electrolyte and lithium anode was summalized in this review. The main strategy includes constructing a "soft contact" at the interface, adjusting the mechanical performance of the solid electrolyte and tuning the deposition dynamics of lithium ions. Furthermore, the perspectives on interfacial modification were presented.

The rapid development of new energy vehicles places a more and more urgent demand for high-performance lithium-ion batteries. As an important part of lithium-ion battery, the electrode performance has a significant impact on the overall performance of lithium-ion battery. In the electrode, the uniformity and stability of the slurry, which is a multi-component mixture, own a great influence on the performance of the electrode sheet. However, most of the current researchers' interests are usually placed after the slurry process, that is, only focus on the performance of the electrode, but ignore the slurry which is the preconditions of the performance of the electrode. Uniformity of the electrode is determined by the uniformity and stability of slurries. However, as a complicated mixture of multicomponent suspended particles, it's hard to measure the uniformity and stability of the slurry directly. At present, the rheological property test of the slurry is the most effective method to characterize the uniformity and stability of the slurry. In this paper, the effects of active materials, binders, conductive agents, solvents, dispersing additives, pH value, temperature, mixing steps on the rheological properties of the slurry during the manufacturing of lithium ion battery electrode pastes were reviewed. The influence of these factors on the rheological properties of the slurry was summarized, which provides a certain guiding role for fabricating slurries with higher uniformity and stability and developing high performance Li-ion batteries.

Carbon nanotubes(CNTs), as an important discovery in the research of nanomaterials, have become a research hotspot in the field of carbon materials since their birth. With its unique porous structure, metal-organic frameworks (MOFs) has been developed into one of the frontiers of research in recent years. With the continuous development of materials science in recent years, the research on composite technology of materials with different functional characteristics has become one of the main methods to solve key problems in the field of materials applications.CNTs and MOFs are two very important types of nanomaterials in the current material field. Combining the high electrical conductivity of CNTs with the high specific surface area and rich pore distribution characteristics of MOFs through composite technology is an inevitable trend for future research and application in the field of materials. In this paper, the main composite forms and preparation methods of MOFs and CNTs in recent years were reviewed, and the latest research progress of composites in the fields of supercapacitors, lithium battery electrodes, catalysis, adsorption, etc. was summarized. The synergistic improvement of the performance of the two materials was discussed and analyzed, and it was pointed out that the composite of CNTs and MOFs materials and the growth and distribution of CNTs have a high degree of randomness, and further control of them is the focus of future technical research.

The friction and wear of mechanical parts mainly occurs on the surface of the material, and about 80% of the failures of parts are caused by surface wear.Friction and wear increase the loss of material and energy, and reduce the reliability and safety.Using laser cladding technology to prepare a high entropy alloy coating on the surface of the substrate can achieve a good metallurgical combination between the coating and the substrate, so as to achieve the purpose of improving surface wear resistance.The main factors affecting the wear resistance of the high entropy alloy coating are the mechanical and physical properties of the coating material (such as hardness, plasticity and toughness), defects generated during the cladding process (such as surface roughness, pores and cracks), friction conditions (such as high temperature environment and corrosive environment).In this paper, the influencing factors and strengthening mechanism of laser cladding high entropy alloy coatings were reviewed and summarized.First of all, the influence of laser process parameters (such as laser power, laser scanning speed, spot diameter) and post-treatment processes (such as heat treatment and rolling) on the quality and performance of the coating were explained.Secondly, the influence of component element selection, high temperature environment and corrosive environment on the wear resistance of the coating was described.Finally, the problems existing in the preparation of high entropy alloy coatings by laser cladding technology were analyzed, and the future development trends were forecasted, such as developing new materials based on far-equilibrium material design theory, using electric field-magnetic field synergy or laser-ultrasonic vibration composite technology to improve the wear resistance of coatings, etc.

The MAX phase of the ternary layered compound and the recently attracted attention of the MAB phase have become the research hotspots in the field of structural ceramics for more than 20 years because of their common characteristics of ceramics and metals. The high damage tolerance and high fracture toughness are different from the essential characteristics of traditional ceramics. The overall development of MAX phase and the latest research progress of MAB phase were briefly reviewed in this article, focusing on the analysis of the effect of multi-scale layered structure on macro-mechanical behavior and its internal mechanism. Based on the results of first-principles calculations, the bond stiffness model was established and the quantitative characterization of chemical bond strength was realized, and more importantly, it was clarified that "sufficiently" weak interlayer bonding is the root cause for the extraordinary mechanical properties of ternary layered ceramics. The magnetocaloric effect (MCE) of Fe₂AlB₂ near room temperature shows the good application prospects of MAB phase compounds in the functional field. After more than 20 years of continuous research, the structure and performance of MAX-phase compounds have gradually become clear. At present, application research for specific scenarios is vigorously carried out all over the world. However, the current knowledge of MAB phase compounds is still very limited. Therefore, synthesizing and characterizing the structure, mechanical properties, physical properties, and service behaviour of existing MAB phase compounds are the important tasks at this stage. First-principles numerical simulation based on density functional theory (DFT) can play an important role, just as in understanding the extraordinary properties of MAX phase compounds and discovering new compounds.

MXene, very recently emerging family of two-dimensional (2D) transition metal carbides and/or nitrides, have attracted a wide range of attention due to unique layered structure, hydrophilicity, high conductivity and catalytic activity.First, synthesis and various applications of MXene in adsorption, photocatalysis and membrane separation were summarized in this review.Then, the effects of structure control, surface modification and composite of MXene on the adsorption performance of MXene and the formation of effective heterojunction, the exposure of active crystal face and the deposition of precious metals on the catalytic performance of MXene based photocatalysts were discussed.The approaches of constructing MXene based separation membrane for separating pollutants and desalinating seawater were described in detail.Finally, the existing problems in the applications of MXene in the field of water treatment were summarized and analyzed, and the prospects of designing MXene based water treatment materials with excellent performance were put forward.

Photonic crystals are dielectric structure materials with photonic band gaps which are composed of matters with different dielectric constants and arranged in space periodically. The slow photon and band gap reflection in the photonic band gap can promote the photonic capture and control the interaction between light and matter. Based on the unique optical properties and large specific surface area of photonic crystals, the photonic crystal structure is introduced into the design of semiconductor photocatalytic materials, which can effectively enhance the photocatalytic reaction activity. The preparation methods of three-dimensional photonic crystals and slow photons effect was introduced in this paper, the research progress was especially summarized in the inverse opal photonic crystal as catalysts in wastewater purification of light, hydrogen production, carbon dioxide conversion and etc, and for the challenge faced by the photonic crystal light catalyst, multilayer three-dimensional photonic crystals with different refractive index and the periodicity were put forward, in order to promote photonic crystals applications in the field of photocatalysis.

Taking the preparation of electrode materials of supercapacitors, the study of properties and the performance of assembled asymmetric supercapacitors as the core contents, and improving the electrochemical performance of supercapacitors as the main purpose, the in-situ polymerization method was used to prepare carboxylated multi-walled carbon nanotubes (PI-MWCNTs) grafted polyimide solution, which is used as the precursor of nitrogen-doped carbon to realize the growth of composites on the surface of carbon cloth and as electrode material.Manganese dioxide-carbon cloth (MnO₂-CC) as the positive electrode, Polyimide-carbon cloth grafted with multi-walled carbon nanotubes as negative electrode (PI-MWCNTs-CC), build asymmetric supercapacitors. The structure and electrochemical properties of the electrode materials were characterized by scanning electron microscopy, raman spectroscopy, surface area and pore size testing, X line photoelectron spectroscopy, cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. According to the study, when the scan rate is 20 mV/s, asymmetric capacitor potential window can be increased to 1.3 V and its volume specific capacity is 1.80 F/cm³.When the power density is 14.08 mW/cm³, the energy density can reach up to 0.423 mWh/cm³.

BN and BN/SiC interphases were prepared on the surface of SiC tows by chemical vapor infiltration (CVI).The tows were furthered deposited a thick SiC layer to form mini SiC composites, whose tensile properties were tested.The surface and cross-section of interphase and mini-composites were observed by SEM.The surface roughness of the interphase was evaluated by AFM.The crystal structure of interphase was characterized by XRD and TEM.The results show that the BN interphase prepared by the CVI method follows Stranski-Krastanov growth mode, possessing smooth surface and weak bonds with the matrix.After heat treatment, the crystallinity and the surface roughness of BN interphase increase, and the bond with the matrix is also slightly enhanced.The BN/SiC interphase follows V-W growth mode, possessing rough surface and weak bonds with the matrix.The tensile strength of mini-composites with BN, HBN and BN/SiC interphases are 970, 1050 MPa, and 1720 MPa, respectively.

Ceramics and metals have large differences in thermal expansion coefficients, which can easily lead to large residual stresses in the joints. The researchers used the method of adding an intermediate layer to successfully reduce the residual stress in the joints. In the present work, using AgCu/Cu foam/AgCu composite filler as interlayer, brazing ZrB₂-SiC ceramics and Inconel 600 alloy has been studied. Microstructure, shear strength and residual stress were studied in details for conditions with different thickness of Cu foam. The results show that with or without the addition of Cu foam, the brazed joints consists of Ag_ss, Cu_ss and (Cr, Fe)₇C₃ phases without obvious defects. Shear strength of brazed joint is improved after introducing the Cu foam. With the increase of Cu foam thickness, the Cu_ss is quantitatively increased, and shear strength is increased first and then decreased. When thickness of Cu foam is 1 mm, the maximum shear strength is obtained as 72.5 MPa. The residual stresses of joint were calculated by using ABAQUS. The residual stress on the metals side is reduced by 50.6 MPa, and the ZrB₂-SiC side by 110.3 MPa of the brazed joint with Cu foam. The results further prove that the addition of Cu foam can effectively reduce the residual stress and improve the shear strength of joints.

To meet the requirements of high energy density and fast charge for energy storage systems and electric vehicles, the high-energy and high-power density lithium-ion batteries have attracted numerous attentions.Designing thick-electrode can significantly increase energy density and reduce cost, and is also compatible with various electrode materials, which makes it one of hottest researches for the development of high-energy density lithium-ion batteries.Thick electrodes usually suffer from poor mechanical properties and sluggish reaction kinetics. Therefore, it is very important to construct a thick electrode with good mechanical properties and fast transport network for lithium ion and electron.The electrochemical behavior and key scientific issues of thick electrodes were firstly analyzed in this review, the current strategies for constructing thick electrodes and their advantages were then introduced, and finally the design principles and the development direction of thick electrodes were pointed out.

Lithium-rich manganese-based cathode material is a promising next-generation lithium-ion battery cathode material, however, it exhibits significant differences in electrochemical performance at different temperatures, which severely limits the application in practical environments. A variety of electrochemical measures were used to characterize the difference in electrochemical performance of lithium-rich material within the temperature range of 5-45℃. The influencing factors of material properties and temperature dependence were analyzed from the perspective of polarization. The results show that the charge/discharge capacity of lithium-rich material decreases with decreasing temperature, which is mainly due to the significant increase in the polarization of the oxygen/manganese ion reaction in the high-voltage and low-voltage ranges with decreasing temperature, resulting in a severe decrease in its capacity contribution.The significantly increased polarization is mainly caused by the poor intrinsic kinetic performance of oxygen/manganese ions, which leading to high apparent activation energy of the charge transfer process. In addition, the participation of oxygen and manganese ions in the charge compensation reaction changes the structure of the material seriously.It induces changes in the composition of the interface film, which increases the apparent activation energy of lithium ion transmission at the interface in the low voltage interval. Moreover, it causes bulk diffusion of lithium ions at the end of the charge and discharge process having higher apparent activation energy. Therefore, improving the oxygen/manganese ion reaction kinetics of lithium-rich material is the main method to enhance its environmental adaptability.

Resin matrix composites have many advantages such as high specific strength and modulus, good fatigue performance, corrosion resistance, and have become the application and development trend of aero engine components under 400 ℃. Foreign research on resin matrix composites for aero engine started earlier, which have been applied in fan blades, fan casings, outer ducts, nacelles and other components of multi-engine, and developed towards the trend of better structure, higher material performance, lower manufacturing cost and higher automation degree. The development foundation of domestic resin matrix composites is good, but compared with foreign countries the application proportion of resin matrix composites in engines in not high. It is necessary to furthur improve the technical level of design, materials, manufacturing, experiment and engineering ability. In this paper, foreign development status was discussed in the field of structures, materials and processing methods of aero engine composite components, the development trend was analyzed and corresponding suggestions were given, from the aspects of building composites system for aero engine, strengthening application research and design guide, promoting the transformation of pre-research achievements and application of automation technology.

With the rapid development of portable and wearable electronic devices, research on flexible energy storage devices has gradually shifted to the directions of miniaturization, softness and intelligence. At the same time, people have higher requirements for the energy density, power density and mechanical properties of the device. As the core part of flexible energy storage devices, electrode material is the key to determining device performance. With the development of flexible energy storage electronic devices, there is an urgent need for new battery technology and fast, low cost and precise control of their microstructure preparation methods. Therefore, the research and development of new energy storage devices such as flexible lithium/sodium-ion batteries, flexible lithium-sulfur batteries, and flexible zinc-air batteries have become the current research hotspots in academia. The current research status of flexible energy storage battery electrodes in recent years was discussed in this paper, the design of flexible electrode materials (independent flexible electrodes and flexible substrate electrodes), and the preparation process of flexible electrode materials of different dimensions (one-dimensional materials, two-dimensional materials and three-dimensional materials) and applications of flexible energy storage electrodes (flexible lithium/sodium ion batteries, flexible lithium-sulfur batteries, flexible zinc-air batteries) were compared and analyzed, and the structural characteristics and electrochemical properties of electrode materials were discussed. Finally, the current problems faced by flexible energy storage devices were pointed out, and the future focus of flexible energy storage devices was the research and development of new solid electrolytes, the rational design of device structures and the continuous optimization of packaging technology.

Composite coatings were prepared by using polisilizane as matric resin and h-BN as functional filler.Raw BN was modified by chemical method to improve its distribution in composite coatings.FT-IR and TEM characterizations were applied to analyse the chemical structure of the raw BN and modified BN samples.SEM was used to observe the microstructure of the as-prepared coatings.The optimal resin content was set as 50% (mass fraction) by characterizing the microstructure of composite coatings with varied resin contents. In addition, basic properties of composite coatings were also tested and analysed.The results show that raw BN is successfully modified using chemical method.The modified BN displays better distribution in composite coatings as expected.The as-prepared coatings have good impermeability and thermal-oxidation resistance.

Requirements for the cockpit of military vehicles are constantly increasing as a result of escalating threats. The traditional transparent bulletproof armor based on glass have been unsatisfactory to relevant application requirements, and lighter and thinner transparent armor based on ceramics is becoming main option. Similar to other bulletproof armor, the main research fields of transparent bulletproof armor include: seek materials with higher performance for armor components; guide the structure design and ballistic test by experiment or computer simulation; understand the main performance of armor materials, the holistic performance of the armor system and the interaction between the components of the whole system more deeply. Based on this notion, the advantages and disadvantages, preparation technology, development, and application situation of the three kinds of ceramic materials commonly used in transparent armor were summarized. Among the three kinds of ceramics, sapphire has the best static parameters. As for the actual effect of bulletproof, the polycrystalline ceramics are better. The main reason for this phenomenon is that the different fragmentation modes of the two kinds of ceramics lead to the difference of projectile-target interaction effect. After that, the crack growth under high strain rate and bullet-proof property of single crystal, polycrystalline ceramics and glass were discussed. Under uniaxial, high strain rate compression, the crack propagation characteristics of materials are sensitive to impact energy/velocity. Polycrystalline ceramics has a composite failure mode of intergranular fracture and intragranular fracture. Under high energy impact, the damage zone of sapphire is similar to polycrystalline ceramics. Lower than critical energy, some sapphire plate orientations damage would be dominated. Finally, the material selection standards and structural design principles of each functional layer were summarized and prospected. Fine grain polycrystalline ceramic materials with high Young's modulus and high hardness are preferred for the strike-layer. Materials with good fracture toughness, high bending stiffness and the ability to localization of the damage within a narrow region should be selected for the intermediate layer. The materials of backing layer require ductility and low density. The bulletproof efficiency of the transparent-armor systems depends on the type and the degree of interaction/integration of different functional layers.

With the rapid development of electric vehicles, people have higher requirement for the energy density and lifespan of power batteries. The cycle performance and rate performance of lithium-ion batteries can be effectively improved through the modification of the positive and negative active materials, the application of new conductive agents and binders, and the optimized design of the electrode group distribution ratio. However, the problems caused by the preparation process of the traditional electrode and the characteristics of the single-layer electrode structure put a limit on the further improvement of the performance of the lithium-ion battery. Therefore, solving the problems of the traditional single-layer electrode structure itself is an important direction of lithium-ion battery research. Three solutions to solve the problems of the single-layer electrode structure by analyzing the related research on the multilayer composite electrode structure were summarized in this paper which are increasing the stability of the electrode surface, increasing the conductivity of the electrode surface and adjusting the internal component distribution of the electrode, and they have their own advantages.By analyzing the characteristics and limitations of different schemes and preparation processes, new directions and ideas for electrode design and engineering application of lithium-ion batteries and other battery systems were proposed in this paper. Finally, the current research status of the multilayer composite electrode structure was summarized in this paper.

Phosphated hydrotalcite (P-LDHs) was synthesized from steel slag and modified hydrotalcite (SDS-P-LDHs) was obtained by intercalation of P-LDHs with sodium dodecyl sulfate (SDS). P-LDHs and SDS-P-LDHs were blended with expanded graphite and ethylene vinyl acetate copolymer (EVA), to prepare EVA foam composites, respectively. The surface morphology and structure of P-LDHs and SDS-P-LDHs were characterized by XRD, XRF, FT-IR, SEM and TEM. Combined with limited oxygen index(LOI), UL-94, SEM, TG, tensile strength and elongation at break, the effects of P-LDHs and SDS-P-LDHs on the flame retardancy and mechanical properties of EVA foam composites were discussed. The results show that the addition of P-LDHs and SDS-P-LDHs significantly improves the flame retardant properties of EVA foam composites and can play a good role in charring formation. Compared with P-LDHs, SDS-P-LDHs have better compatibility with EVA matrix. When the addition amount of SDS-P-LDHs is 30%(mass fraction), the LOI reaches 27.5%, UL-94 reaches V-0 level, tensile strength and elongation at break are 2.27 MPa and 251%, respectively. The comprehensive properties of the system are optimal.

Interface is a key factor affecting the comprehensive performance of magnesium matrix composites, and how to carry out interfacial modulation has been a hot research topic in magnesium matrix composites. Focusing on three types of interface structures of magnesium matrix composites (coherent, semi-coherent and incoherent) and two key issues (interfacial wettability and interfacial reaction) affecting the interface properties, the research progress of interface optimization schemes was reviewed in this paper and the guidelines for the design and regulation of interfacial structures to achieve good interfacial bonding were proposed: good wettability and slight interfacial reaction. In view of the improvement of interface properties of magnesium matrix composites, the addition of rare earth elements can be considered in the future to purify the interface and improve wettability. The matrix and reinforcement are selected according to engineering needs to obtain composite materials with excellent performance in certain aspects. New reinforcement surface coatings will be developed to fully enhance the capabilities of interfacial bonding. First-principles and other computational simulation methods will be used to deeply explore the relationship between interface structure and interface performance.

MXenes, as a new 2D transition metal carbides/nitrides/carbonitrides, have wide potential application in physics, chemistry, material science and nanotechnology fields. Since MXenes inevitably possess defects and —O, —OH, —F terminal groups during the preparation, behaving high conductivity and large surface area, MXenes have a good electron transfer rate and can be used as an excellent electrochemical catalyst. In this review, the various synthesis methods and development of different doping types of MXenes were introduced. The application and mechanism of MXenes in electrocatalytic hydrogen production, oxygen production, oxygen reduction, CO₂ reduction and nitrogen reduction processes were mainly discussed. It was pointed out that the preparation methods of MXenes should possess the characteristics of environmental friendliness, morphology controllability, the inoxidizability and high adjustability, meanwhile, different types of MXenes should be applied to different electrocatalytic reactions.

Functional polymer material is a type of polymer materials with special functions such as catalysis, conductivity, photosensitivity, and biological activity. They have the function of transmitting, converting, or storing substances, energy, and information. Functional polymer materials have the characteristics of light weight, numerous varieties and strong specialty, which make them widely used in machinery, information technology, biomedicine and other fields. The development of functional polymer materials is very rapid. In order to meet the needs of new technologies in various fields, functional polymer materials are gradually developing towards multi-function such as electromagnetic materials and photothermal materials. With the emergence of smart polymers, functional polymer materials are gradually being developed towards intelligence, such as self-healing functional polymer materials and shape memory materials. The research progress of functional polymer materials in recent years was summarized in this article and their applications were briefly described, with emphasis on reactive functional polymer materials, optical functional polymer materials, electrical functional polymer materials, biomedical functional polymer materials, environmentally degradable polymer materials, shape memory polymer materials and smart polymer hydrogel. At present, most functional polymer materials only have traditional functions such as photoelectricity or special functions such as shape memory. It is believed that functional polymer materials with both traditional and special functions will be the development direction of future materials.