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Carbon paper is one of the most commonly used materials for the gas diffusion layer of proton exchange membrane fuel cell, and its performance is the premise to ensure the stable operation of the cell. In order to improve the structure and properties of carbon paper and make it better meet the performance requirements of fuel cell, this study was conducted to press different amounts of graphite plates in the carbonization process to control the applied pressure and analyze the microstructure evolution and mechanism of carbon paper under different pressure. In addition, the effects of applied pressure on the in-plane resistivity, pore size distribution, surface roughness and mechanical properties of carbon paper were also studied. The results show that applying pressure helps to restrain the cracking of resin carbon, reduce the generation of cracks and improve graphitization degree of carbon paper to a certain extent. Furthermore, with the increase of applied pressure, the surface roughness of carbon paper is reduced gradually, while the average and maximum apertures also decrease. When the applied pressure reaches 3600 Pa, compared with the samples without pressure, the in-plane resistivity of carbon paper decreases from 17.15 mΩ·cm to 12.79 mΩ·cm, the tensile strength and flexural strength are improved by 150% and 82.9% respectively.

Whisker multiwalled carbon nanotubes (WMWCNTs) and multiwalled carbon nanotubes (MWCNTs) were synthesized via chemical vapor deposition (CVD), and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Raman spectroscopy. Paper fibers were used as matrix material, WMWCNTs and MWCNTs as functional material. Paper fibers were mixed with dispersed WMWCNTs and MWCNTs by speed-cutting procedure in water. Then the composite papers were fabricated by vacuum filtration method. The electrochemical performance of the supercapacitor was tested by cyclic voltammetry, galvanostatic charge/discharge. The testing results indicate the supercapacitor has a maximum capacitance of 120F/g at a scan rate of 1mV/s and has a specific capacitance of 51.5F/g at 0.4A/g. The maximum energy density and power density reach 63.7Wh/kg and 3.99kW/kg respectively in the current range of 0.4-1.4A/g.

Nano silicon and multiwalled carbon nanotubes(MWCNTs) composites were used as active materials, paper fiber as substrate, MWCNTs as conductive agent, MWCNTs conductive paper was obtained to replace the copper foil current collector and applied in silicon based lithium ion battery. The morphology and the electrochemical performance of the composites were analyzed by scanning electron microscopy (SEM),transmission electron microscopy(TEM), galvanostatic charge-discharge tests and electrochemical impedance spectroscopy(EIS) tests. The results indicate that the lithium ion battery with MWCNTS paper/nano silicon composites reaches a specific capacity of about 1000mAh/g after 50 cycles in the current density of 80mA/g, and has good cycle stability even in the high current density of 2000mA/g.

As the lightest metal structural materials, magnesium and its alloys have great potential to achieve lightweight products in the future. However, magnesium has a high corrosion sensitivity, and the magnesium hydroxide film formed on the surface is loose and porous with little protection, which leads to its application being limited. How to improve the corrosion resistance of magnesium has become a worldwide problem that restricts its application. Alloying is one of the ways to radically improve the corrosion resistance of magnesium alloys. In this paper, the corrosion mechanisms of pure magnesium and the mechanisms of alloying elements on the corrosion performance of magnesium alloys are described in terms of the influence of alloying elements on the corrosion resistance of magnesium and its alloys. In addition, protection mechanisms produced by alloying elements on magnesium alloys were compiled, and the protection mechanisms and corresponding characteristics of beneficial elements on magnesium alloys were summarized. This can provide some reference for the development of new magnesium alloys and the improvement of the corrosion resistance of magnesium alloys. In addition, this paper contributes to a better understanding of the corrosion behavior of magnesium alloys. At present, there is no magnesium alloys can be as good as aluminum alloys or stainless steels corrosion resistance, so the development of corrosion-resistant magnesium alloys needs further research. This paper provides a theoretical basis for the interaction between elements in magnesium alloys, which can provide ideas for the development of new corrosion-resistant magnesium alloys. The synergy between the elements will have a significant impact on the design, process and performance of new corrosion resistant magnesium alloys, and as the research progresses, it is expected that new corrosion-resistant magnesium alloys similar to "stainless steel" will be constructed.

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.

Near β titanium alloy is widely used in automotive and aerospace industries due to their high strength-to-weight ratio and high corrosion resistance. The near β titanium alloy can precipitate ω phase and α phase after solution and ageing treatment, the strength of which can be remarkably increased, usually at the expense of ductility. It is one of the most important structural components of load-bearing that usually as aircraft skin, shell plating, main frame, linker and special fastener. The alloy used in this paper is a self-developed Ti-Al-V-Mo-Cr-Zr-Fe-Nb ultra-high-strength β titanium alloy, which is a typical near β titanium alloy. The characteristic of isothermal phase transformation of near β titanium alloys is diversity and complexity, which is sensitive to temperature and directly affects the mechanical properties after ageing. In this paper, the microstructural evolution and mechanical properties of a Ti-Al-V-Mo-Cr-Zr-Fe-Nb ultra-high strength β titanium alloy after isothermal treatment were investigated by scanning electron microscopy(SEM),transmission electron microscopy(TEM) and micro-hardness tester. The results show that only the isothermal ω precipitates are formed during ageing at 300℃, and the size of isothermal ω phases increase with the ageing time. The isothermal ω precipitates are first precipitated during ageing at 400℃. With the extension of the ageing time, the α phase nucleation occurs near the ω/β interface. No α precipitates are obtained in the alloy aged at 500℃, and needle-like α precipitates are directly precipitated from the β matrix, which is evenly distributed in the β matrix in a "V" shape. Tensile test shows that the tensile strength of the alloy is 1716.1 MPa and the elongation is 2% after ageing at 400℃ for 12 h. The tensile strength of the alloy is 1439.8 MPa and the elongation is 9.84% after ageing at 500℃ for 12 h, and has a good combination of strength and toughness.

Magnesium batteries with the advantages of low cost, high energy density and high safety are expected to be applied in large-scale energy storage and power vehicles in the future. However, magnesium batteries are still in the early development, and cathode is the key reason that limits the battery performance. The high charge density of Mg2+ results in slow diffusion of Mg2+ in cathode materials. Therefore, how to improve the electrochemical performance of cathode materials is the focus and difficulty in the field of magnesium batteries. By analysing the related researches, six strategies for improving the electrochemical performance of cathode materials were summarized in this paper, namely, reducing the particle size, using the shielding effect of the solvent, increasing the interlayer distance, regulating anions, exploring new structures and developing double ion batteries. By clarifying the root cause that makes the strategies effective and pointing out the advantages and limitations of the strategies, this paper provides valuable guidance for the development of high-performance cathode materials for magnesium batteries. Finally, the development status of magnesium battery cathode materials was summarized, and the future development trend of cathode and the whole battery system was prospected.

As one of the core hot components of aeroengines, the safe service of turbine blades is crucial to the operation of aeroengines.When the aeroengines encounter some emergency conditions, the turbine blades may suffer overheating, the temperature of which is much higher than the highest normal operating temperature. Overheating can lead to serious microstructural degradation and even premature failure of turbine blades. In this paper,the methods of overheat inspection and failure analysis were introduced, as well asthe effects of overheating on the microstructural degradation and mechanical propertiesof aeroenginesturbine blades. In addition, the damage assessment, life prediction and microstructure rejuvenation of superalloys after overheating were prospected in this paper, which provide a guidance and theoretical basis for the degradation evaluation and failure analysis of turbine blades as well as the development of new superalloys.

Due to its unique optical and electrical properties, p-type metal oxide materials stannous oxide has been favored by more and more people in various fields such as catalysis, sensing and optoelectronic devices.This paper focuses on the research and application of stannous oxide in thin film transistors. As a core component of display driver panels, thin film transistors play an important role in the display.The research progress of p-type stannous oxide thin film transistors was summarized in this paper, which includes the analysis of the microcosmic properties of stannous oxide, the preparation of stannous oxide thin film materials and the fabrication methods of transistors. By introducing the crystal and electronic structure of stannous oxide in details, the microcosmic regul-ation mechanism of the properties of tin oxide was discussed. Through the preparation of stannous oxide materials and the research and application of the devices, the problems of low current-to-switch ratio faced by stannous oxide thin film transistors were analyzed and their prospects in the direction of the complementary metal-oxide-semiconductor devices were put forward, in order to provide a refere-nce for the preparation of p-type metal oxide thin film transistors which are stable and eco-friendly.

As a biodegradable material,magnesium alloys has been attracted by more researchers, recently. Due to good biocompatibility, mechanical properties and biodegradable absorption charac-teristics, it has been honored as revolutionary biological materials. However, current bio-magnesium alloy still could not meet the requirements of clinical application, due to its shortcomings of rapid corrosion rate and local corrosion. In this paper, the progress of bio-magnesium alloy in improving the corrosion performance was reviewed from the aspects of high purity, alloying, heat treatment process and surface modification. The paper makes a prospect on how to develop the biodegradable materials with better corrosion performance in terms of adding non-toxic alloying elements, proper surface coating, advanced preparation technology and heat treatment process.

With the progress of global population aging and the incidence rate of bone and joint diseases, the demand for bone repair medical metal materials is increasing.Bio-metallic materials include non-degradable (i.e. titanium) and degradable metals (i.e. magnesium and iron). However, metals are insufficient in corrosion resistance and osseointegration, so their surface modification needs to be optimized. It is noted that strontium (Sr) has the effect of promoting osteogenesis and inhibiting osteoclasts, and thus the use of Sr as a modified component is of great significance for improving the activity of bone cells on biomedical metal surfaces. In this paper, the corrosion resistance and biocompatibility of strontium doped coatings on titanium, magnesium and iron in recent years were summarized and compared.This article focuses on the research on improving the osseointegration performance of composite coatings prepared by combining strontium and carriers with good degradability and biocompatibility(such as hydroxyapatite, brushite, etc.) on the surface of titanium alloy, magnesium alloy and iron alloy. Finally, it is believed that the application of strontium-containing coatings on the surface of metal materials has a wide range of prospects, and it was proposed that the combination of strontium and zinc make the metal materials have antibacterial properties while promoting bone repair.It was expected to provide reference for promising clinical applications of strontium-doped coating.

Biomedical magnesium alloys exhibit high specific strength, low density, proper elastic modulus, biodegradability, good biocompatibility and biomechanical compatibility, thus show extensive application perspective in bone fixation and cardiovascular stent.However, fast and nonuniform corrosion of magnesium alloys may easily cause the premature loss of mechanical integrity that restricts their clinical application in load bearing. In this paper, the research progress of magnesium alloys was systematically reviewed from the aspects of corrosion modes, the intrinsic and external factors affecting corrosion resistance, improvement of intrinsic corrosion resistance and surface modification, and the future development trend of corrosion resistance of biomedical magnesium alloys was prospected. On the one hand, the corrosion resistance of magnesium alloys can be improved by means such as low alloying, high purification and fine crystallization. On the other hand, reliable coatings are designed from the aspects of corrosion resistance, antibacterial and drug loading. In addition, corrosion media, flow field, stress and other in-body service factors should be considered comprehensively to study the corrosion degradation behavior and mechanism of magnesium alloy implanted devices.

In this paper, the research status of photocathodic protection in broadening light absorption range, enhancing electron-hole separation rate and conduction efficiency of electrons, and realizing protection in the dark were discussed. Six modification methods were summarized, including modification of conductive polymers, construction of heterojunction, composition with two-dimensional conductive materials, adjustment and control of topography, doping with metal or non-metallic elements and coupling with energy storage semiconductors. The problems, such as short duration of protection in the dark and low repeatability of some experiments, were pointed out. The unsolved technical difficulties, such as overcoming insufficient natural light intensity, the harsh conditions of electrolyte solution and the complexity of photocathodic protection system design, were analyzed. Finally, several solutions to above problems were proposed, such as the development of semiconductor materials driven by natural light, the preparation of colloidal electrolyte and capsule material for storing electrolyte, and the design of photocathodic protection coatings.

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.

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.

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.

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.

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.

To meet the development needs of advanced aeroengines,the structure of aeroengine turbine blades is becoming increasingly complex, and the content of refractory elements is increasing in single crystal superalloys, which are the preferred materials for turbine blades. As a result, the tendency to form the grain defects increases during the preparation of single crystal turbine blades, which directly affects the quality of single crystal turbine blades. In this paper, a kind of grain defect that appears in the directional solidification process of single crystal superalloys—freckle was discussed. The research works on the formation mechanism, the criterion model and the control method of freckles formation during the directional solidification of single crystal superalloys in recent years was reviewed. The influence of the alloy composition, blade structure, directional solidification process and crystal orientation of single crystal castings on the formation of freckles was analyzed. Considering the influence of the alloying elements in different alloy systems and the parameters of the directional solidification process on the freckle formation, further studying the freckle formation mechanism of the single crystal turbine blade with complex structures, establishing an effective method for prediction and control of freckles are the future research directions.

With the rapid development of electronic equipment and wireless communication in recent years, problems of electromagnetic interference are also becoming more and more serious. It is urgent to develop high performance electromagnetic interference(EMI) shielding materials to alleviate the damage of electromagnetic interference. MXene(Ti3C2Tx) is a novel kind of 2D material with ultrahigh electrical conductivity and unique chemically active surface, and therefore exhibits extremely excellent electromagnetic shielding performance. The preparation, structural feature and EMI shielding mechanism of Ti3C2Tx were focused and introduced in this paper,the latest research progress on EMI shielding applications of Ti3C2Tx-based films and 3D porous materials was objectively reviewed and evaluated, and the main problem at the present was analyzed. In addition, the future development direction and tendency of Ti3C2Tx-based EMI shielding materials from the aspects of preparation, microstructure control and structure design and so on were also prospected in this poper,based on current development needs including developing low-cost, green and efficient Ti3C2Tx preparation methods, solving the long-standing oxidation problem of Ti3C2Tx, designing new structure of Ti3C2Tx-based EMI shielding materials and finding out other MXenes EMI shielding materials other than Ti3C2Tx, which can provide new ideas and guidance for the further development of the next generation of high-performance EMI shielding materials.

Silicon has been a pivotal material for the next generation lithium-ion batteries, owing to its superior theoretical capacity (4200 mAh·g-1). However, the huge volume change of silicon during the process of lithiation/delithiation will lead to the instability of silicon-based anode. As a main composition of electrode, the binder plays a critical role in connecting the electrode components together and maintaining the stability of electrode, the use of an appropriate binder is essential to improve the cycling stability of silicon-based anode. Water-soluble binders which have abundant functional groups have received extensive attention due to their excellent performance in improving the electrochemical performance of silicon-based anodes. In this paper, the research progress of water-soluble binders used in silicon-based anode was reviewed. First, the properties of one-dimensional linear binders were summarized. On this basis, the research progress of composite binders with three-dimensional (3D) network structure was mainly introduced. The structure and properties of different 3D network binders were systematically analyzed. Finally, the preferred structure and properties of the water-soluble binders for silicon-based anode were proposed, and a train of thought for water-soluble binders’ choice and design was provided.

Hydrotalcite applied in mechanical friction system exhibits good friction and wear resistance. Friction performance of hydrotalcite as lubrication oil (grease) additive and its influence factors were summarized systematically in this paper. The mechanism and regulation of preparation methods, cation radius, the ratio of divalent and trivalent cations, the type of inorganic anions between layers, the intercalation of organic anions, crystallinity on the friction reduction and antiwear properties were analyzed comparatively. The basic principle and control directions of the structural composition design of hydrotalcite lubrication materials were clarified. Based on the research status, it was suggested that the industrial test verification of hydrotalcite, the evaluation of the influence of hydrotalcite on the quality of lubricating oil (grease), and the basic research about the interaction between hydrotalcite and the friction surface should be strengthened.

Currently, the utilization efficiency of energy still remains at low level, although the depletion of fossil fuel is approaching. Therefore, while vigorously developing new energy, it is of great significance to develop new materials with "passive self-adjustment ability". Phase change humidity storage composite materials is a kind of composite material with phase change and temperature controlling property and humidity storage and humidity controlling property, which are very promising in the field of building wall material. In this paper, the action principle of phase change humidity storage composite materials, packaging technique of phase change material, classification and selection of humidity-controlling material were introduced briefly in the first section. And then the application of phase change humidity storage composite materials in building wall material were reviewed and analyzed in detail. In the third part, characteristics of double-shell phase change micro-nano capsules, polyfatty acid/SiO2 phase change and humidity storage composite materials and decanoic acid-palmitic acid @ Ce-La/TiO2 composites were pointed out. Main problems and research status of phase change humidity storage composite materials were pointed. Finally, it was pointed out the optimized durability of phase change humidity storage composite materials, developing multi-functional phase change humidity storage composite materials are the main development directions of phase change humidity storage composite materials.

Numerical simulation can establish corresponding models for temperature field, molten pool shape, residential stress, microstructure evolution in the metal SLM process effectively. Meanwhile this model can accurately predict the performance of forming parts, and provide scientific basis for process parameters optimization, consequently boost the metal SLM to industry application. In this paper, the latest research progress of numerical simulation in the process of metal laser additive manufacturing was summarized, including temperature field, molten pool dynamics, residual stress and deformation in the forming part, and microstructure change.The latest progress of numerical simulation in metal SLM process was summarized, and the metal SLM process was analyzed. Finally, the future development trend was put forward that metal SLM process numerical simulation should be combined with big data, artificial intelligence, deep learning and other technologies and numerical simulation accuracy will be further improved,the processing window of metal laser additive manufacturing will be broadened,and guidance will be provided for the development of individual products.

Metamaterials have drawn extensive attention for their fine regulation of electromagnetic waves at subwavelength scales. They have abundant electromagnetic modes, and support highly confined and enhanced electromagnetic fields on the surface which are highly sensitive to the surrounding dielectric environment, so they can be used in label-free optical biosensing. Compared with traditional optical biosensors, metamaterial biosensors have many advantages, such as miniaturization, integration, high sensitivity and multi-function customization. The recent progress of metamaterial biosensors in visible light and near infrared, middle infrared, and terahertz spectrums was summarized in this paper, including refractive index biosensing, surface-enhanced Raman scattering, surface-enhanced infrared absorption, and terahertz biosensing.

Chemical reactions based on the characteristics of silicon-oxygen bonds and different conditions are important methods to construct new organic/inorganic siloxane functional materials with very different structures and unique properties, which have aroused widespread attention in the academic community. The new silicon-oxygen functional materials have both organic/inorganic compound properties, and are widely used in many fields for their good biocompatibility, high and low temperature resistance, and electrical insulation properties. The research fields and development status of the design, synthesis and application of siloxane compounds were reviewed in this paper, focusing on the design and synthesis methods of linear structure (one-dimensional structure), nonlinear structure (two-dimensional structure), polyhedral oligomeric silsesquioxane compounds (three-dimensional structure) and organic/inorganic hybrid siloxane compounds, and the application progress of siloxane compounds in biomedicine, aerospace, functional materials and tertiary oil recovery will be promoted by studying stretchable polysiloxane elastomer, siloxane compound coating, new silicone functional materials for oil displacement and so on.

NiTi-based shape memory alloys (SMAs) are one of the SMAs with most outstanding properties, and have been widely applied in aviation, space, electronics, construction, biomedicine and other fields. In recent years, the elastocaloric refrigeration based on elastocaloric effect (eCE) of NiTi alloys has attracted increasing attentions since their excellent mechanical properties, huge elastocaloric strength and good machinability. However, conventional binary NiTi alloys cannot meet the requirements of long-life service since their large superelastic stress hysteresis and poor cyclic stability of superelasticity and eCE. In this paper, the research progress of eCE for NiTi-based alloys was reviewed. The effect of doping alloying element, thermomechanical treatment and novel processing techniques on eCE of NiTi-based alloys were surnmarized. In addition, the developed elastocaloric devices or prototypes based on NiTi-based alloys were also briefly introduced. However, the current researches on NiTi-based elastocaloric materials and the development of prototypes are still in the experimental stage. To realize their commercial application requires further in-depth research and optimization. In the future, the research priorities for the former will concentrate on material miniaturization, alloying or applying special treatment as well as changing circulation methods and so on. On the other hand, the research priorities for the latter will focus on improving heat transfer efficiency, strengthening heat exchange, reducing friction and other losses, and improving mechanical loadings as well as circulation modes.

Gradient aluminum honeycomb structure is an effective energy-absorbing structure. According to the concept of gradient rate, four types of aluminum honeycomb sandwich components with the same mass and different gradient rates were designed by changing the cell wall length of the honeycomb core layer. On the basis of the same mass, the deformation mode of gradient aluminum honeycomb sandwich structure under quasi-static state, as well as the dynamic response and energy absorption characteristics of layered homogeneous honeycomb structure under impact load and layered gradient honeycomb structure with different gradient rates were compared by combining quasi-static compression experiments and the deformation and mechanical properties of gradient aluminum honeycomb sandwich structures under quasi-static and impact states, which were simulated by nonlinear finite element. The results show that during the quasi-static compression process, the deformation of the aluminum honeycomb gradient sandwich panel has obvious localization characteristics. The deformation of the honeycomb core is preferentially low density until compaction, and the densification strain difference between the layers is gradually decreased as the core layer density is increased. Besides, under high-speed impact, the gradient honeycomb panel is not strictly deformed step by step in the quasi-static process until it is densified. It is the linear elastic deformation, elastic buckling, plastic collapse and compaction that occur as a whole under the interaction of the hammer head inertia and the core layer density. In addition, during the range of the gradient rate designed in this paper, when the gradient rate is γ1=0.0276, the energy absorption of the gradient honeycomb sandwich panel is the best. Compared with a homogeneous honeycomb sandwich panel of the same mass, the energy absorption is improved by 10.63%.

Ti-Ni-Hf alloy is one of the most potential high temperature shape memory alloys due to the various advantages such as higher phase transformation temperature, relatively lower cost and larger output work. However, the plastic deformation takes place prior to the reorientation of martensitic variants due to the lower matrix strength, which results in the poor shape memory properties. To date, the measures of improving the strain recovery characteristics consist of thermo-mechanical treatment (cold rolling + annealing), alloying, aging treatment and fabrication of single crystal etc. It has been revealed that the strain recovery performances of Ti-Ni-Hf alloys are closely related to the microstructural features. In the present paper, the recent progress in the field of Ti-Ni-Hf high temperature shape memory alloy was presented, mainly consisting of microstructural evolution, martensitic transformation behaviour, mechanical properties and strain recovery features, moreover, the relationship between the microstructure, martensitic transformation as well as the mechanical and strain recovery characteristics was established, based on the previous research results. At present, the poor cold or hot workability of Ti-Ni-Hf high temperature shape memory alloy is the bottleneck which limits its extensive applications. Hence, the future research may focus on the powder metallurgy and additive manufacturing of Ti-Ni-Hf high temperature shape memory alloy.

Thermoplastic composite materials are widely used in automobile, aerospace and military fields due to their advantages of high impact toughness, recyclability and excellent environmental adaptability. However, the high viscosity of the thermoplastic resin after melting makes it difficult to impregnate the fiber adequately. As the intermediate material of composite materials, the preparation of prepreg has been relatively mature. The fibers in the prepreg have been impregnated with resin, so the composite material prepared by the prepreg has fewer voids. The preparation method of thermoplastic prepreg and analysis of the advantages and disadvantages of various preparation methods were introduced in this paper, including solution impregnation, melt impregnation, powder impregnation, film stacking lamination, commingled yarns and reactive of chain growth impregnation. The impregnation mechanism of melt infiltrated fibers was described and some research results of impregnation mechanism were summarized. The effects of parameters such as immersion temperature, immersion pressure and traction speed on the properties of prepreg were discussed. Finally, the main problems and the development direction in the production of prepreg were summarized. In the future, methods such as multidisciplinary integration, fiber and resin modification and computer simulation of the impregnation process can be used to promote the industrial development of thermoplastic prepreg.

Soda lime/aluminosilicate glass is widely used in commercial and national defense industries due to its excellent physical properties such as high strength and high hardness. Fatigue fracture is one of the main failure modes of glass. Investigating the fatigue behavior is of great importance to its processing, life prediction and failure prevention. In this paper,the fundamental and experimental methods of static fatigue and dynamic fatigue of soda lime/aluminosilicate glass were reviewed.The conclusions obtained by comparing the fatigue behavior of soda lime silicate and aluminosilicate glass demonstrate that the threshold load for radial crack initiation of raw soda lime silicate glass is much lower than raw aluminosilicate glass, the threshold load for radial crack initiation of chemically strengthened soda lime/aluminosilicate glass is increased with the surface compressive stress; the crack growth rate of raw soda lime/aluminosilicate glass increase with fictive temperature and this phenomena is more evident in aluminosilicate glass; the raw soda lime/aluminosilicate glass shows a loading rate-dependent strength while the chemically strengthened aluminosilicate glass does not. Consequently, the effect of different stress state and environment atmosphere on the behavior of static fatigue and dynamic fatigue of static fatigue and dynamic fatigue is an important issue to be studied.

Nickel-based cast superalloy is one of the main materials applied in the manufacture of aeroengine and gas turbine,and it is widely applied in aerospace,energy industry and shipbuilding industries etc.The rapid development of modern aviation industry is inseparable from the rapid improvement of the comprehensive performance of superalloys, and the application of hot isostatic pressing technology in the field of nickel-based casting superalloys plays a pivotal role in improving the comprehensive performance of nickel-based casting superalloys. In this paper, the working principle and application history of hot isostatic pressing technology were introduced. The research and application status of hot isostatic pressing technology in the field of nickel-based casting superalloys was summarized. The research on the effect of hot isostatic pressing on the densification mechanism and microstructure properties of cast superalloys, research on hot isostatic pressing on the microstructure repair of nickel-based cast superalloys in long-term service, and research on the realization of the diffusion bonding of two nickel-based superalloys progress are highlighted and elaborated. At the same time, some problems in the research of hot isostatic pressing technology and the development trend of domestic hot isostatic pressing technology in the field of nickel-based cast superalloys were pointed out.

As the demand for large-scale batteries for electrical energy storage is increasing, sodium-ion batteries have attracted a lot of attention due to the abundance,cost-effectiveness of sodium resources and resemblance with lithium. In the key material selection of sodium ion battery, electrochemical performance and safety of a sodium-ion battery were affected by the electrolyte, which not only decides the electrochemical window and energy density, but also controls the electrode/electrolyte interfaces. In this paper, the basic requirements and classification of electrolyte of sodium ion battery were reviewed. The selective requirements of electrolyte in sodium ion batteries, the physicochemical properties of different sodium salts and the effects on solid electrolyte interface were discussed. Based on the compatibility of different solvents and materials as well as the energy storage mechanism of materials in different solvent systems, the solid electrolyte interface, rate and cycling performance obtained by materials in ether and ester based electrolytes were analyzed. Finally, the future development of sodium ion battery electrolyte in terms of matching with materials and key characterization methods were prospected.

Most common chemiresistive gas sensors, based on metal oxide semiconductors, have high energy consumption and poor gas response, which are not suitable for gas detection in factory. With the development of the research on 3D graphene, 3D graphene and its composites become a hotspot of gas sensor researches, because of its large specific surface area and high electrical conductivity. In this paper, the fabrication, performance and application of gas sensors based on 3D graphene and its composites were summarized.At the same time,in view of the slow response recovery speed and small production scale of the current 3D graphene-based gas sensor,solutions such as miniaturization and intelligent production of the sensor chip were proposed,so that it can become the front end of the industrial Internet of Things in the future.

Resin matrix composites have been widely used in aviation, aerospace and other important frontiers. The application proportion of composites has become an important criterion to measure equipment advancement. Thermoset composite materials are well known difficult to be repeatedly processed and recycled, while thermoplastic composite materials show poor processing performance due to the high melting temperature. Nowadays, the growth of dynamic covalent chemistry has obscured the line between thermosets and thermoplastics, which makes it possible to realize the innovative development of resin matrix composites. In this paper, the fundamental theory of dynamic covalent chemistry and covalent adaptable networks were outlined. The research process of resin matrix composites based on dynamic covalent chemistry was introduced in detail. The resin matrix composites exhibit promising prospect owing to the remoldable, ease to recycle, self-healing and smart actuator applications. Finally, some suggestions were put forward for the development of the composites, such as improving bond exchange reaction mechanism and stress relaxation model, developing high-performance and commercial resin systems, also developing technologies for composites forming, connecting, repairing and recycling based on the characteristics of material.

The rapid development of photocatalytic technology has attracted attention in the field of decontamination of chemical agents (CWAs). Owing to high-efficiency, broad-spectrum, and environmentally friendly features, photocatalytic technology can overcome many problems encountered by traditional decontamination technology, such as the problem of soil corrosion, and is suitable for the degradation of CWAs. Researchers have conducted a lot of researches on this, and there are also related reviews to discuss in detail the mechanism and application of photocatalytic degradation of CWAs. However, there are many pieces of literature on traditional photocatalytic materials, and few have summarized the mechanism and application of new photocatalytic materials in the degradation of CWAs. Therefore, in this paper, the mechanism of photocatalytic degradation of CWAs, species of photocatalytic materials, the application of photocatalytic degradation of CWAs, especially the researches of new photocatalytic materials, such as metal-organic frameworks, degradation agents were summarized in detail. Photocatalytic technology has advantages over other technologies in the treatment of low-concentration, refractory CWAs. However, the research is still in the laboratory stage and is mostly simulated agent experiments. There are still obstacles when applied to the degradation of real CWAs. In the future, wearable photocatalytic protective materials may be worthy of further research. At the same time, photocatalytic technology has proved to have certain potential in the large-scale destruction of poisons.

Polymer matrix composites (PMCs) have become one of the most important structure materials in the new generation of civil turbofan aeroengine due to their advantages of high specific strength, high specific stiffness, good designability, excellent vibration damping performance and feasible integrity fabrication. The PMCs application in aeroengine abroad based on fan blade, fan casing, acoustic liner and bushing was introduced firstly in this paper. The advantages of PMCs in structure optimization, economy and environmental friendliness were also illustrated. Moreover, new progress of PMCs including micro/nano material hybridization, 3D printing process and metamaterials in aeroengine was analyzed in details. Finally, some suggestions about PMCs application based on the relationship of "design-material-process-evaluation" were proposed for further development of civil turbofan aero engine in China.

The non-isothermal reaction kinetics of cyanate ester system was investigated by dynamic differential scanning calorimetry (DSC). The analysis of non-isothermal data was carried out by using the model-fitting Kissinger, Flynn-Wall-Ozawa, and Crane methods. The results indicate that the apparent activation energy of the curing reaction is 101.3 kJ·mol-1 and 99.4 kJ·mol-1calculated from Kissinger and Flynn-Wall-Ozawa models, respectively. The reaction sequence of the adhesive is 0.92 calculated from Crane model. In addition, the relationship of the curing degree with the curing temperature and the curing time is established. The curing parameters are obtained by adopting "T-β" and "t-β" extrapolation, and the strength test proves the validity of the curing parameters designed in this paper. These results constitute a theoretical basis for the curing and application of the cyanate ester adhesives.

TiO2 nano-film type gas sensor has the advantages of simple preparation method, high sensitivity, good consistency and miniaturization, and the wide band of TiO2 semiconductor enables it to greatly improve the performance of the sensor by coating other elements. Nowadays, it has received more and more attention from researchers. In this paper, the research progress of TiO2 gas sensor at home and abroad was reviewed. The application of TiO2 thin film gas sensor in the detection of six common reducing gases(H2, NH3, H2S, VOC, CO, SO2) and two common oxidizing gases(CO2 and NOx) was introduced. In the application of gas detection, the sensing performance and sensing mechanism were discussed and the future research and development of TiO2 thin film gas sensor were prospected such as doping conductive particles, precious metals or metal oxides into TiO2 to improve its performance, which provides a reference for the study of new gas sensor.

Among the manufacturing methods of high performance gradient functional materials, laser additive manufacturing technology can achieve the materials with gradient microstructure and property through precisely controlling the powder feeding and corresponding process adjustment, providing a new way to prepare high performance gradient functional materials more conveniently and efficiently. The basic principles and classification of laser additive manufacturing technology for high performance gradient functional materials were introduced in this paper, and the research progress in manufacturing high performance gradient functional materials by laser additive manufacturing technology at home and abroad was summarized. Furthermore, the shortcomings of this research field in material selection, process optimization and process monitoring were proposed, and its future research directions, such as the establishment of standard systems, in-depth theoretical research and the development of new manufacturing systems, were prospected, which provide guidance for the research of laser additive manufacturing technology for high performance gradient functional materials.

Supercapacitors are power-type energy storage devices with high power density and long cycle life. However, the low energy density limits wider applications. In this paper, the working principle of supercapacitors was first introduced, and the characteristics of electrode materials needed and current progress were summarized. Then, the characteristics and related progress of aqueous, organic and ionic liquid electrolytes were introduced. Finally, the principle and the factors of energy density limitation of supercapacitors were pointed out, and the improvement methods were discussed from the aspects of electrode materials, electrolytes and the structure of supercapacitors, respectively.

The stimulus-response composite is a kind of intelligent material, which usually possesses the characteristics of self-perception, autonomous response, shape memory, adaptive and self-healing. The stimulus-response materials used in 4D printing were reviewed in this paper, and the application research progress of 4D printed shape memory composite hydrogels and shape memory polymers (SMPs) and their composites was focused. Finally, the application status of 4D printing in the biomedical and aerospace fields was summarized, and the development trend and application prospect of 4D printing were prospected. 4D printing is an emerging manufacturing technology. Although various printing methods, printable smart materials and driving methods have been developed, 4D printing still faces many challenges in practical engineering applications. Novel printing technologies, smart materials, structural design and modeling software need to be developed to facilitate the practical application of 4D printing in the fields of soft robotics, biomedicine, aerospace and intelligent electronic equipment.

GH4720Li superalloy has been widely employed in high-performance aero engines turbine disks and other rotating component due to the excellent high temperature strength, anti-fatigue, corrosion resistance and long-term structural stability. The mechanism of function and evolution rule of γ'phase in GH4720Li superalloy was summed up in this paper. The relationship between γ'phase and high-temperature properties and the interaction law of γ'phase and residual stress were analyzed. In addition, the research progress of the new superalloy which was designed on the basis of GH4720Li superalloy was summarized, the future application of partitioned cooling technology and dual-organization dual-performance disk preparation technology was prospected.

The three-dimensional (3D) woven composites have the advantages of strong structural design ability, overall near-net shape of complex components and high impact damage tolerance, and have become the focus of the development of new materials in the aerospace industry. In recent years, the structural design, micro-modelling and performance analysis of 3D woven composites have been rapidly developed and achieved substantial achievement. The development of multi-axial woven structures, fine modeling, and automated continuous production are the development trends of 3D woven composites. In this paper, the structural characteristics of typical 3D woven preforms were introduced. The quasi-static mechanical properties of 3D woven composites with different structures were discussed. The research progress of the micro-structure modelling, theoretical analysis and numerical simulation of 3D woven composite materials were reviewed. The typical applications of 3D woven composite materials in aerospace were listed, which can provide reference for the application research of 3D woven composite materials.

Continuous fiber reinforced high-performance thermoplastic composites have gradually attracted the attention of the composite industries due to their unique advantages such as light mass, high strength, good impact resistance, short molding cycle, secondary molding and waste recycling. The application status of continuous fiber reinforced high-performance thermoplastic composites was introduced in this paper starting from several kinds of high-performance thermoplastic resins. Moreover, the forming and properties of continuous fiber reinforced high-performance thermoplastic composites were also summarized in detail. At last, the future development trend of domestic continuous fiber reinforced high-performance thermoplastic composites was summarized from three aspects including application demand, molding process and material properties, in order to promote the structural design and application of continuous fiber reinforced high-performance thermoplastic composites.

The exceptional electronic, thermal, optical and mechanical properties of graphene make it ideal for the next generation of electronic and optoelectronic devices. So, it is particularly important to research and develop high-quality, large-scale and low-cost technology of graphene preparation. Electrochemical exfoliation of graphite has emerged as a promising wet chemical approach with advantages such as scalability, solution processability and eco-friendliness. In this paper, research progress of preparation of graphene by electrochemical method was reviewed. The effects of anodic oxidation and cathodic intercalation of graphite on the yield, morphology, quality and defect level of graphene were emphatically described, and the exfoliation mechanisms of the two processes were briefly summarized. Moreover, the preparation and application of functionalized graphene by electrochemical approach were introduced. Finally, it was pointed out that the future development direction of electrochemical preparation of graphene is the design of electrolyte system, optimization of exfoliation conditions, understanding of the exfoliation mechanism, rational design of electrochemical cells.

Due to its one-atom thickness,excellent optical and electrical properties, graphene has great potential applications in fields of transistors, solar cells, supercapacitors and sensors. For further development of practical applications, controllable synthesis of high-quality graphene is of great importance.Because of its advantage in in-situ growth on various substrates at low temperature, plasma-enhanced chemical vapor deposition(PECVD) has become one of the most promising strategies for the synthesis of graphene in the future. In this paper, the effect of several key factors on the growth of graphene by PECVD,such as plasma power, temperature, substrates and pressure was summarized. Two growth mechanisms including nucleation and coalescence mechanism and etching and edge growth mechanism were reviewed. Furthermore, the challenges and development of graphene were also discussed. In future work, the controllable preparation of graphene on the nucleation and growth of graphene will be essential to achieve large-area and high-quality graphene by PECVD at low temperature, laying the foundation for the application of graphene synthesized by PECVD in electronics and other fields.

The mass production of graphene sheets is a prerequisite for exploiting the applications of graphene. A major focus of experimental research has been concentrated on the development of effective approaches to produce well-defined graphene in large scale. Due to its high yield and cost efficiency, chemical reduction of graphene oxide has been proofed to be one of the most feasible approaches to achieve this goal. Graphene consists almost entirely of sp2 hybridized carbon atoms, while graphene oxide additionally contains sp3 regions, oxygen functional groups and structural defects. The fundamental understanding of the mechanism of chemical reduction of graphene oxide is a key issue when preparing graphene materials via graphene oxide precursor. Although dozens of methods have been exploited to facilitate the chemical reduction of graphene, only few studies were focused on the reduction mechanism.The chemical reduction strategies of graphene oxide, and as well as their mechanisms were reviewed in this paper. It was suggested that the core issue of the reduction is how to clarify the removal of hydroxyl groups and the simultaneous restoration of a conjugated structure.

Magnetic nanomaterial has been widely used in water treatment due to its high biocompatibility, good adsorption performance, and easy solid-liquid separation. In this paper,the classification, common form, and functional methods of iron-based magnetic nanocomposites as adsorbents to remove heavy metal ions were summarized. The functional principle of iron-based magnetic nanoparticles and the adsorption mechanism of these materials in adsorption process were discussed. In addition, the unsolved problems, include the agglomeration, oxidation, and unstability of iron-based magnetic nanomaterial applied in wastewater treatment were analyzed. Finally, the functionalization on the iron-based magnetic nanomaterial for the removal of heavy metal ions was prospected, which provides more adequate theoretical basis for heavy metal ions in wastewater treatment.

With the increasing development of the microwave absorption materials, nitride material has attracted more attentions, and is expected to become a new kind of potential microwave absorbing materials due to their excellent physical and chemical properties. In this paper, the research status of nitride microwave absorbing materials was discussed, and the research status of titanium nitride, iron nitride, manganese nitride, boron carbon nitride and alloy nitride was summarized in detail. Finally, the developing trend of nitride materials was prospected from the aspects of morphology control, bionic structure design, high temperature microwave absorption and microwave absorption mechanism.