With the rapid development of consumer electronics, electric vehicles and energy storage, it is urgent to improve the energy density of secondary energy storage devices represented by lithium-ion batteries. Cathode materials are a key issue to improve the energy density of lithium-ion batteries. Li-rich Mn-based layered oxide cathode materials (LRM) are considered as one of the most promising cathode materials for lithium-ion batteries due to their extremely high theoretical specific capacity (>350 mA·h·g^-1) and reversible specific capacity (>250 mA·h·g^-1). However, the low initial Coulombic efficiency, poor rate performance, and rapid voltage and capacity fading of LRM cathode materials seriously restrict their industrial application. This review introduced the research progress of the crystal structure and electrochemical mechanism of LRM cathode materials, and analyzed the problems of LRM. The modification strategies of LRM cathode materials were comprehensively introduced from the aspects of morphology design control, doping, coating, defect structure design, gradient composition design, layered/spinel heterostructure construction, and electrolyte additives. We provided some ideas and guidance for the future development of LRM cathodes to ultimately promote the practical application of LRM cathode materials.

Precursor continuous silicon carbide (SiC) fiber has a wide application prospect in the fields of aviation, aerospace and nuclear energy. The oxidation behavior and kinetics data of SiC fiber in a high-temperature oxidation environment are rather important for the research of composites. This review summarized the research work on continuous SiC fiber by a precursor method, oxidation type, performance degradation mechanism, oxidation process and oxidation kinetics of SiC fiber, and put forward the future research directions on oxidation behavior of SiC fiber.

Natural nano-clay with kaolinite is widely used in photocatalysis. This review represented research progress on the photocatalysis of nanoclay with kaolinite as traditional support, functional support and photocatalyst. A relationship between the structure and photochemical properties of kaolinite was analyzed. In addition, the challenges and future development were also prospected.

The theoretical models for the application of low-field nuclear magnetic resonance (LF NMR) to the cementitious materials are reviewed, in response to the three common questions, namely the data reliability, result stability and model validity problems. The major applications, including the characterization of pores, the quantification of hydration products and the diffusion dynamics, are linked to four theoretical models, namely the two-fraction fast-exchange model, the Korb model, the amplitude model and the cryoporometry related Gibbs-Thomson model. In addition, the limitations in models as well as in instruments are pointed out. In particular, for the mentioned applications, most commonly used pulse sequences together with recommended parameters are provided. Based on the latest progress in the field, challenges and outlooks are discussed.

The addition of chemical admixtures has been an effective approach to improve the performance of cementitious materials. Working mechanisms of the chemical admixtures in molecular scale still need to be clarified. Calcium silicate hydrate (C-S-H), as the main hydration product of cement, determines most macroscopic properties of cement-based materials. Molecular dynamics simulation has been an effective technique to reveal the interaction between chemical admixture molecules and C-S-H and its effect on the properties of C-S-H at the molecular/atomic scale. In this paper, recent progresses in molecular dynamics studies of the interaction between chemical admixtures (organic and inorganic) and C-S-H were reviewed, and their impacts on properties of C-S-H are briefly summarized. In addition, the future research direction of molecular dynamics simulation of chemical admixture-(C-S-H) system is prospected. The summarized chemical admixtures include organic admixtures such as small organic molecules, resins and fibers, water-soluble polymers, and inorganic admixtures such as (modified) graphene, silene, carbon nano-tubes, and various nanoparticles. Most molecular dynamics simulation research focuses on the interaction between the admixtures and C-S-H interface. Understanding of such interfacial interaction is the key to reveal the working mechanisms of the admixtures in improving the mechanical properties of C-S-H. In addition, for admixtures such as small organic molecules, water-soluble polymers and some nanoparticles, a large number of studies have used molecular dynamics method to describe the microscopic processes such as the adsorption of the admixture molecules on C-S-H surface, intercalation into C-S-H layers, aggregation of the admixtures that blocks C-S-H layered structure, so as to clarify the mechanism of these admixtures on the mechanical properties, transport properties and even shrinkage behavior of C-S-H. These understandings provide theoretical inspiration for improving the properties of cement-based materials and for designing the molecular structure of admixtures more effectively.

High activity and durable structural catalysts are increasingly needed for carbon monoxide (CO) catalytic removal of industrial flue gas. A series of structural catalysts were prepared by coating polymetallic oxide catalyst on cordierite honeycomb supports. The results showed that silica sol and hot air drying could promote the powder catalyst to evenly and compactly spread on the surface of the support, and improve the anti-shedding performance and catalytic performance of the structural catalyst. The coating shedding rate of the optimized catalyst after 60 min of ultrasonic vibration was 0.97%. The catalytic efficiency of 99% CO can be achieved at 7 500 h^-1 space speed, 1% CO, 8% water vapour content and 110 ℃, and remains stable within 72 h. The CO catalytic efficiency can be stabilized above 86% after 720 h in actual sintering flue gas condition.

Degradation of cement-based materials with the infrastructure engineering constructed in 20 th century for the end of service-life is increasingly concerned. Acoustic emission (AE) as an intrinsic physical phenomenon of energy emission happening inside material or structure can effectively support a precise sensation of health of material and structure based on its spatiotemporal information. This review briefly introduced the sensing principle and analysis method of AE and summarized the supports from AE to description of degradation process, influence factors, and cement-based material degradation such as alkali aggregate reaction, corrosion induced cracking, fatigue damage, and freeze-thaw spalling. In addition, the potential aspects to enrich AE research on the degradation of cement-based materials were also discussed via considering the time-dependent and large-scale feature of hydraulic structure.

The phase-change energy storage materials are used in the field of building insulation to achieve a purpose of transferring peak temperature loads and reducing building energy consumption. Well-dispersed two-dimensional montmorillonite nanosheets were prepared, and the energy storage material-paraffin was encapsulated via the adsorption on the surface of its pores (cavities) to form a thin shell structure. The effects of paraffin concentration and cetyltrimethylammonium bromide concentration on the montmorillonite nanosheets and their encapsulation were investigated. The thermal storage properties of the phase-change energy storage composites were analyzed. The phase-change energy storage composite material was applied to the building insulation board, and the mechanical properties and heat storage and temperature regulation performance of the phase-change energy storage insulation board were examined. This composite material can effectively improve its thermal resistance, delay the appearance of peak temperature, and improve the comfort of the indoor living environment, while maintaining the mechanical properties of the insulation board. This work could provide a guidance for the development and application of novel building energy-saving materials.

Scintillator is a core device in X-ray imaging technology. It can convert absorbed X-ray or other high-energy charged particles into visible light, and it is widely used in medical diagnosis, radiation dose measurement and safety inspection. At present, most commercial scintillators are single crystal or thin film materials, which have complex preparation process, long growth cycle, high cost, as well as poor irradiation stability and imaging effect. In this paper, ZnS quantum dots glass-ceramics (GC) as a low cost and weather resistance scintillator for X-ray indirect imaging was prepared through in-situ precipitation of ZnS quantum dots (QDs) into transparent glass matrix. The experimental results show that the emission peak of ZnS GC is located at 518 nm under X-ray irradiation, and the fish bone and chip are imaged by X-ray imaging system. The image contour is clear, the internal structure of the object is clear, and the imaging resolution reaches 18.0 lp/mm due to the uniform distribution of ZnS quantum dots in the glass matrix. Also, the damaged ZnS GC scintillator can completely recover its imaging performance by simple heat treatment at a cumulative dose of 288 J/kg. It is indicated that ZnS GC as a scintillator has a broad application prospect in the field of high resolution X-ray imaging.

WO₃ electrochromic devices (ECDs) with the short response time and high optical contrast show great application potentials in car rearview mirrors and smart windows. With the rapid development of wearable electronics, the fabrication of flexible WO₃ films for bendable ECDs has attracted much attention. However, the fabrication of flexible crystalline WO₃ films generally requires a sophisticated vacuum vapor deposition technique, including magnetron sputtering and electron-beam deposition due to the high crystallization temperature of WO₃ and the limited endurable temperature of polymer substrates. The dense WO₃ layers on polymer substrates affect the facile access of electrolyte and fast intercalation/deintercalation of electrolyte ions. In this paper, well-crystallized WO₃·H₂O microplate powders were pre-synthesized by a chemical reflux method. Monoethanolamine was utilized to intensively dissociate WO₃·H₂O microplates into a well-dispersed colloidal solution. The flexible nanocrystalline WO_x/polyethylene terephthalate films were fabricated via spin coating deposition and assembled into the flexible ECDs. The accumulated charge repulsion provided by the intense interfacial interaction between amine group and WO₃·H₂O microplates results in their fast dissociation. The fabricated flexible crystalline WO_x electrochromic devices have short coloring and bleaching time of 5.9 s and 5.4 s, respectively, and a coloring efficiency of 146.7 cm²/C, and still exhibit the superior performance after 200 bending cycles.