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

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

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

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

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

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

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

Graphene, as a representative of two-dimensional (2D) materials, has excellent intrinsic properties such as high specific surface area and conductivity, but its macroscopic bulk behaves poorly owing to severe face-to-face restacking and hand-in-hand contact resistance. Three-dimensional (3D) design of 2D materials can deliver the excellent nanoscaled properties to the macroscopic world, to realize the high surface area, conductivity, interconnected pores, and good mechanics of the bulks. It is necessary and highlighted to develop the porous monolith of 2D materials for applications as electrodes, adsorbents, elastomers, etc. The blowing route has the advantages of low cost and simple processing, which has been accentually developed to produce the foams of 2D materials for several years. This article introduces the principle of the blowing method, summarizing the recent examples of blown foams of graphene, boron nitride nanosheet, and others. The scientific front about foams of 2D materials is discussed, and the broad applications of the new materials are prospected in energy, environment, etc.

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

Anode material is an important component for Li-ion battery. The current anode materials are mainly based on graphite, which possesses low theoretical specific capacity of 372 mAh/g, and thus hinder the further development of Li-ion battery. Among the newly developed anode materials, metal oxides have recently attracted intense attention due to their high theoretical specific capacity, low cost and environmental friendliness. However, metal oxides own poor electrical conductivity and large volume changes during cycling. Nanosizing can overcome these disadvantages while maintaining the advantages for metal oxide based anode materials, and thus becomes a research hot spot. Herein, we review the recent research advances of the nanostructured metal oxides as anode materials, mainly focusing on the microstructure design and performance optimization of representative metal oxides and their composites. In addition, some suggestions are presented for further explorations in relative fields.

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

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

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

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

Boron nitride aerogel is a kind of new nanomaterials with three-dimensional porous network structure, which takes solid as the framework and gas as the dispersion medium. It has high specific surface area, high porosity, low density and other excellent properties. In addition, compared with graphene aerogels, it exhibits better insulation, oxidation resistance, thermal stability and chemical stability. These outstanding properties make it promising application in the fields of gas adsorption, catalysis, sewage purification, thermal insulation/conduction. This article systematically reviewed the preparation methods of boron nitride aerogels including the hard template method, soft template method, low-dimensional boron nitride assembly method, and template-free method in the light of domestic and foreign research status. Moreover, the important applications of boron nitride aerogels in key fields are summarized, and the future development direction is prospected.

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

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

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

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

Proton Exchange Membrane Fuel Cell (PEMFC) has the characteristics of high energy conversion efficiency, high power density, fast start-up at room temperature, low noise and zero pollution, which is expected to alleviate the energy crisis and reduce carbon dioxide emissions. It has broad application prospects in rail transit, aerospace and other fields. Catalyst is one of the key materials of PEMFC. Moreover, Pt catalysts are widely used and considered difficult to be replaced because of their good activity and stability in oxygen reduction reaction. Pt is expensive because of its limited storage. However, Pt loading could be significantly lessened by Pt support to improve PEMFC utilization. Carbon materials are widely used as Pt supports because of their low cost, high specific surface area, pore structure, adjustable conductivity and surface properties, but commercial carbon black supports have low utilization efficiency and poor electrochemical corrosion resistance for Pt. For realizing the large-scale application of PEMFC, it is necessary to develop new carbon supports which can uniformly disperse Pt, efficiently utilize Pt, be resistant to electrochemical corrosion, and have good conductivity, thus the performance and sustainability of PEMFC are improved. Carbon aerogels, carbon nanotubes, graphene and other new carbon supports with unique structures and properties, which are expected to improve PEMFC performance and life, have attracted the attention of many researchers. In this paper, the research progress on new carbon material as Pt support for PEMFC in recent years is reviewed systematically, and the development trend is also commented appropriately.

A lightweight, environmentally-friendly thermal insulation coating was experimentally applied to the carbon fiber to reinforce epoxy resin composites. The coating is mainly composed of bonding layer, barrier layer and reflective layer, and prepared by using titanium dioxide, silica, aluminum oxide and hollow glass microspheres as function fillers. The addition of waterborne polyurethane with a thermal expansion coefficient of 120×10 ^-6 K ^-1 as a film-forming material, is to solve the problem of cracking caused by the mismatch of the thermal expansion coefficients of the coating and the substrate material. The results show that after being applied the coating, can solidify within 24 h at room temperature. When the thicknesses of the bonding layer, the heat barrier layer and the reflective layer were 80, 120, and 90 μm, the thermal insulation coating has the best performance with reflectance of the coating higher than 0.95, the thermal conductivity at 0.048 W·m ^-1·K ^-1 and the temperature difference as high as 20.1 ℃. After being subjected to thermal shock at 190 ℃ for 6 times, and the maximum weight loss rate of the coating was 3.7%, indicating the coating highly stable. When kept at 160 ℃ for 4 h, its surface turned yellow without falling off, and its nano filler particles still remained stable.

Semiconductor photocatalytic water splitting has been considered as a potential strategy to overcome global energy shortage and environmental pollution. In recent years, phosphorene (BP) attracted great attention in photocatalytic water splitting due to its adjustable band gap, high hole mobility and wide absorption spectrum. This review summarizes the recent significant advances on designing high-performance BP-based photocatalysts for water splitting. The synthetic methods and modification strategies (e.g., surface modification and heterostructure design) of BP-based photocatalysts are described. Furthermore, in order to elucidate the structure-activity relationship of BP-based photocatalysts, the charge transfer mechanism is illustrated. Finally, the ongoing challenges and opportunities for the future development of BP-based photocatalysts in the exciting research area are highlighted.

The mechanism of Fe-N/C catalysts in oxygen reduction reactions is critical to the development of efficient, sustainable non-noble metal catalysts in polymer electrolyte membrane fuel cells, but it is still in controversy. In order to understand the relationship between composition and the nanostructure of material and the electrochemical activity, this study developed a type of Fe-N/C catalyst with high electrochemical activity, which contained Fe-N_x active sites and Fe/Fe₃C nanocrystals encapsulated with nitrogen-doped carbon nanotubes. Despite being free of precious metals, the as-prepared catalyst displays high oxygen reduction reactions (ORR) activity in alkaline medium with the half-wave potential of 0.86 V(vs RHE), the mass activity of 18.84 A/g at 0.77 V(vs RHE), and the maximum current density of -4.3 mA·cm ^-2. Meanwhile, the electron transfer number is 3.7 at 0.2 V(vs RHE), revealing that the 4-electron ORR reaction exists in the catalyst. The excellent electrochemical activity is attributed to the graphene-encapsulated metallic Fe/Fe₃C nanocrystals which improves the conductivity after the growth of N-doped carbon nanotubes, and the relatively high proportion of Fe-N_x active sites distributed on the surface of Fe/Fe₃C nanoparticles. This study provides a certain reference and basis for the further study of non-noble metal catalyst and their wide application in commercial production.

With continuous development of electronics, the requirements for power supply systems are increasing. Supercapacitors (SCs), which have high energy density and excellent power output performance, are ideal power supplies for new generation of miniaturized, intelligent and wearable electronic devices. Thus, developing SCs with fast charge-discharge speed and high stability is a key research topic in the field of energy storage. As the most important part of SCs, electrode materials are critical to its performance. Due to the excellent performances of high-ordered pore structure, large specific surface area, diverse morphologies and dimensions, and adjustable conductivity, conductive metal-organic frameworks (MOFs) materials have shown great potential as promising SCs electrode materials, and have attracted wide attention. This review introduces the structure, conductive mechanism and preparation methods of conductive MOFs following a short introduction of SCs, describes its design strategy as SCs electrode materials, reviews the research progress of conductive MOFs in the field of SCs, and prospects its future application.

The treatment of oily wastewater has become a worldwide problem. How to effectively separate the oil-water mixture has become an urgent problem to be solved. Here, the environmental friendly and simple dipping surface modification method was used to modify the melamine sponge (MS) by using a mixture of graphene oxide (GO) and polytetrafluoroethylene (PTFE), and superhydrophobic material (GPMS) was successfully prepared. Structure, morphology and composition of the obtained GPMS were analyzed by X-ray diffraction (XRD), thermogravimetric (TG), Fourier transform infrared spectroscope (FT-IR), and scanning electron microscope (SEM). Its surface wettability, compression cycle, selective adsorption performance, and continuous oil-water emulsion separation performance were systematically studied. The results show that the GPMS is superhydrophobic with hydrophobic angle up to 168°. It can undertake 50 compression cycles, selectively adsorb both floating oil and underwater heavy oil, and efficiently separate oil-water emulsion. Therefore, the GPMS is a kind of potentially applicative oil pollution control material.

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

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

Carbon nanospheres enriched with α-MoC_1-x nanocrystalline (α-MoC_1-x/CNS) were synthesized by self-assembly and applied as a mediator for the surface of commercial polypropylene (PP) separator. Compared with pristin PP separator, the cycling stability and rate performance of the lithium-sulfur batteries with the modified α-MoC_1-x/CNS-PP separator are significantly improved and the battery with α-MoC_1-x/CNS-PP separator exhibits an initial discharge capacity of 1129.7 mAh/g at 0.5C and retains 855.5 mAh/g after 100 cycles with above 98% Coulombic efficiency. Remarkably, the capacity loss rate is only 7.7% after 48 h static storage. Combined with the morphology and XPS analysis of α-MoC_1-x/CNS, it is found that the designed α-MoC_1-x/CNS-PP separator prevents the migration of lithium polysulfide to the anode during the process of charge and discharge in lithium sulfur batteries. Formations of Mo-S bonds, thiosulfate and polythionate are attributed to the contact between lithium polysulfide and α-MoC_1-x/CNS, which further restrains active material in cathode region and improves the performance of lithium- sulfur batteries consequently.

Zinc-manganese (Zn/MnO₂) batteries with outstanding advantages of high operation safety, high environmental benignity and high cost performance, is suitable for the application of large-scale energy storage battery. However, the uncontrolled growth of zinc dendrites on the metal zinc anode during charge-discharge cycling causes serious problems such as quick capacity decrease and short circuit failure. In this study, the aqueous electrolyte was converted into a composite quasi-gel electrolyte by adding hydrophilic nano-silica (SiO₂) and sodium alginate (SA), which effectively inhibits the dendrite growth of the surface of the zinc negative electrode and the capacity degradation of the Zn-MnO₂ battery. Galvanostatic charge-discharge tests showed that the Zn/MnO₂ battery with composite gel electrolyte achieves a capacity retention of 78% after 1800 cycles, while the capacity of Zn/MnO₂ battery using ordinary electrolyte almost fails after 1000 cycles. The three-dimensional network structure of the gel electrolyte can improve the distribution uniformity of zinc ion in electrolyte, reduce the capacity decay rate and failure risk of the batteries.

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

Lithium metal anode, due to its highest theoretical specific capacity (3860 mAh·g ^-1) and lowest electrochemical potential (-3.04 V (vs SHE)), has become the first choice of the next generation of electrochemical energy storage devices. It is known as the “holy grail” of the battery industry. However, the disadvantage of lithium metal battery is particularly obvious: during the charge and discharge process, lithium metal battery is easy to deposit unevenly on the anode electrode, resulting in lithium dendrite which causes the continuous rupture and formation of solid electrolyte interface (SEI) film. The unstable SEI film, intensifying the formation of lithium dendrites and then piercing the separator, causes a decline for the battery cycle performance and the safety hazard. Therefore, it is particularly important to take corresponding measures to make lithium metal uniformly deposited on the anode. In this study, the uniform lithiophilic copper oxide nanosheet array formed on the surface of commercial copper mesh through oxidation of alkaline solvent and calcination of air. The 3D structure of copper mesh can effectively reduce the current density, and the lithiophilic nanosheet array can effectively reduce the overpotential of lithium deposition simultaneously. This lithiophilic 3D copper-based current collector makes lithium deposited uniformly and effectively, and inhibits the formation of lithium dendrites. In the half-cell test at a current density of 3 mA·cm ^-2 the battery circulated stably for 230 cycles with Coulombic efficiency remaining above 99%. The lithium iron phosphate (LFP) full battery with the as-prepared material as current collector worked stably for more than 300 cycles at 1C(0.17 mA·mg ^-1) and present a capacity retention of ~95%. This study provides a new design strategy of 3D current collector for stable lithium metal batteries.

Photocatalysis technology possesses great potential in the field of oxidation of nitrogen oxides due to the low energy costs and little secondary pollution. Bismuth carbonate (Bi₂O₂CO₃, BOC)/polypyrrole (PPy) was prepared at room temperature to remove NO under visible light irradiation. After being decorated with PPy, the NO removal efficiency of BOC is enhanced from 9.4% to 20.4% while the generation of NO₂ is reduced from 2% to approximately zero, which are attributed to the oxygen vacancy formed at the interface between BOC and PPy via interfacial hydrogen bonding. Photocurrent and electrochemical impedance spectra indicate that oxygen vacancies promote the separation and migration of photo-induced electrons and holes over BOC, hence improve its photocatalytic activity. Furthermore, the presence of oxygen vacancy promotes the formation of more •O₂ ^-, and then improve the NO oxidation activity and safety of BOC together with •OH.

Aspirin/layered double hydroxides composite (A-LDHs) and aspirin/layered double hydroxide-nanosheets composite (A-LDHs-NS) were prepared by intercalation and exfoliation-recombination, respectively. Their morphology, drug loading property and drug loading mode of the composites were characterized by XRD, SEM, TG-DTG, and FT-IR. The releasing performances of aspirin from A-LDHs and A-LDHs-NS in the phosphate buffer solutions with different pH conditions were investigated. The results show that the typical lamellar structures are hold in as-prepared LDHs and LDHs-NS. The larger specific surface area (187 m ²·g ^-1) of LDHs-NS, the more aspirins are loaded on its surface, among which the max drug loading is 1.178 mmol·g ^-1. Its releasing process lasts for more than 1440 min, much longer than 20 min of the control materials, showing excellent sustained-releasing performance. This performance may because of the strong interaction between aspirin and LDHs-NS. Moreover, the sustained releasing performance is stronger at pH 7.4 than that at pH 4.8. All data from this study provides a reference for wider application of this kind of two-dimensional materials in biomedicine.

In thermoelectric (TE) devices, the interfacial reliability greatly influenced devices’ durability and power output. For skutterudites (SKD) devices, TE legs and electrodes are bonded together with diffusion barrier layer (DBL). At elevated temperatures, DBL react with SKD matrix or electrode to generate complex interfacial microstructures, which often accompanies evolutions of the thermal, electrical and mechanical properties at the interfaces. In this work, a finite element model containing the interfacial microstructure characteristics based on the experimental results was built to analyze the interfacial stress state in the skutterudite-based TE joints. A single-layer model was applied to screen out the most important parameters of the coefficient of thermal expansion (CTE) and the modulus of DBL on the first principle stress. The multilayer model considering the interfacial microstructures evolution was built to quantitively simulate the stress state of the TE joints at different aging temperatures and time. The simulation results show that the reactive CoSb₂ layer is the weakest layer in both SKD/Nb and SKD/Zr joints. And by prolonging the aging time, the thickness of the reaction layer continuously increased, leading to a significant raising of the interfacial stress. The tensile testing results of the SKD/Nb joints match the simulation results well, consolidating accuracy and feasibility of this multilayer model. This study provides an important guidance on the design of DBL to improve the TE joints’ mechanical reliability, and a common method to precisely simulate the stress condition in other coating systems.

Hydrolysis is a unique method for hydrogen generation at ambient condition. Widespread attentions have been paid to materials for hydrogen generation via hydrolysis due to several advantages: high theoretical hydrogen capacity, moderate storage and operation condition, safety, etc. In this paper, recent progress and development in this area were reviewed. Three types of materials including borohydride (NaBH₄, NH₃·BH₃), metal (Mg, Al), and metal hydride (MgH₂) were introduced. Several issues about them were discussed specifically: mechanism, main problems, designments of catalysts and materials, etc. Based on these discussions, we compared the different materials mentioned above, commented their current performances and practical difficulties. At last, prospects in this field were presented.

New intercalated compounds Pd_xNbSe₂ (x=0-0.17) were synthesized via solid-state reaction. They possess the parent structure of 2H-NbSe₂ and crystalize in the hexagonal space group of P6₃/mmc. The intercalated Pd occupies the octahedral position in the van der Waals gaps of 2H-NbSe₂. Unit cell parameter c increases linearly with the Pd content, while a is nearly unchanged. The lattice parameter of Pd_0.17NbSe₂ (a=b=0.34611(2) nm, c= 1.27004(11) nm) is identified by single crystal X-ray diffraction. The intercalated Pd stabilizes the crystal structure of NbSe₂ by connecting the adjacent Nb-Se layers with [PdSe₆] octahedra and leads to the enhanced thermostability in air. Temperature dependence of electric resistivity reveals that the residual resistivity ratio of Pd_xNbSe₂ monotonically decreases with addition of the intercalated Pd content. The decreased superconducting critical temperature of Pd_xNbSe₂ indicates the suppression effect of Pd intercalation on the superconductivity in the host NbSe₂.

Ethylene is the main factor of postharvest spoilage of fruits and vegetables. Therefore, how to reduce or remove the ethylene released during the storage of fruits and vegetables is a problem to be solved. In this study, a series of nickel foam supported TiO₂/WO₃ were prepared by Sol-Gel method. The samples were characterized by different methods. The photocatalytic degradation activity of ethylene under ultraviolet light irradiation was investigated. The results show that TiO₂/WO₃ film is successfully supported on the nickel foam, and there formed heterojunction between TiO₂ and WO₃, which efficiently enhanced the separation and transfer rates of photogenerated electron and hole. The narrowed band-gap also leads to a red shift of optical absorbance and high photoactivity. The photocatalytic activity and stability of TiO₂/WO₃ were excellent under UV light irradiation. When the mass percentage of WO₃ is 6% of TiO₂, the photocatalytic ethylene degradation of the TiO₂/WO₃ composite film reaches maximum, and the degradation rate constant is almost 9.8 times as that of TiO₂. The mechanism of photocatalytic degradation of ethylene by TiO₂/WO₃ supported on nickel foam under ultraviolet light irradiation was also discussed.

Porous bioceramic scaffolds, which possess attractive biocompatibility, ability to guide tissue regeneration and porous surface morphologies and channels beneficial to ingrowth of new born tissues, have seized increasing attentions and been widely applied in the field of hard tissue restoration. Whereas, the weak osteoinductive activity, monotonous biological function and poor mechanical property have restrained the therapeutic efficacy and wider application of bioceramic scaffolds. In view of this, we intended to introduce the existing modification methods of bioceramic scaffolds, including the surface modification with functional coating, construction of surface micro-/nano- structures, functional element doping and enhancement of mechanical property, along with the state of the research progresses in the improvement of biocompatibility, bone defect restoration, drug delivery, tumor therapy, and antibacterial capacity of multifunctional bioceramic scaffolds. In addition, potential research directions and applications of functionally modified bioceramic scaffolds are prospected to provide references for the related exploration afterwards.

To investigate the modification mechanism of mixed heterogeneous on photocatalysis, a series of Nd³⁺-doped BiVO₄ photo-catalysts with different Nd³⁺ contents were synthesized through a facile hydrothermal reaction. The samples exhibit Nd³⁺ content-dependent phase transition from monoclinic to tetragonal phase, as demonstrated by XRD and Raman analyses. SEM images show that the phase transition is accompanied by obvious morphology variation. Less than 1at% Nd³⁺-doped monocline BiVO₄ is composed of irregular particles, while more than 7at% Nd³⁺ doping results in tetragonal phase BiVO₄ of sphere-like or kernel with groove surface. When Nd³⁺content is in the range of 1at%-7at%, the micron cuboid bars appear in the samples. More importantly, monoclinic and tetragonal phase is concomitant in the product and a heterogeneous junction with staggered band structure is formed. The Rhodamine B degradation efficiencies of all Nd³⁺-doped samples are higher than those of undoped samples due to the regular morphology after doping. The formed heterogeneous junction inhibits photo-generated electrons and holes recombination of Nd³⁺-doped BiVO₄, inducing 99.4% catalytic efficiency in 4at% Nd³⁺-doped sample. The novel morphology and the intrinsic mechanism of photocatalysis enhancement upon Nd³⁺-doped BiVO₄ are obtained from the synthesis strategy and the energy band structure.