Solar thermal radiant energy is abundant in storage and pollution-free, and is one of the most competitive clean energies in the future. In recent years, halide perovskite quantum dots (PQDs) are widely used in solar cells and luminescent concentrator solar cells due to their excellent photoelectric properties and unique advantages such as quantum confinement effect and solution processing, and possess vast application prospects, but they are still facing many challenges in future commercial applications. In this review, optimization strategies for improving cell performance are emphatically summarized combined with the domestic and foreign research progress in the field of PQD solar cells. The application of PQDs in luminescent concentrator cells is introduced. Finally, the current challenges in this field are elaborated, and its development trends are prospected. This review provides some ideas for the design and development of the photovoltaic technology in the future.

Silicon carbide fiber reinforced silicon carbide (SiC_f/SiC) composites have become the preferred candidate for structural applications in advanced nuclear energy systems, because of their low neutron toxicity, neutron irradiation tolerance and high-temperature oxidation resistance. In recent years, both academia and industry either domestic or abroad have carried out a lot of researches on SiC_f/SiC composites for nuclear application, and numerous important achievements have been made. This paper summarized and analysed some critical directions of SiC_f/SiC composites for nuclear applications, including nuclear-grade SiC fibers, fibre/matrix interfaces, composite processing, modeling and simulation, corrosion behavior and surface protection, joining technology, as well as radiation damage. The key issues and potential solutions of SiC_f/SiC composites for nuclear applications have been pointed out in account to the requirements, anticipating to be beneficial to promoting further researches and final applications.

Flash sintering is an electric field assisted sintering technology which has attracted much attention in recent years. This review introduces its origin, development, and basic characteristics. In the study of flash incubation and initiation process, the nonlinear conductivity characteristics and electrochemical blackening phenomenon are narrated, and the defect mechanism dominated by oxygen vacancy is recounted. As for rapid densification during flash sintering, it is proposed that the generation and movement of defects caused by electric field produce Coulomb force between powder particles, which is conducive to density in the early stage of flash sintering. Meanwhile, the densification process is accompanied by the rapid movement of metal cations. In terms of grain growth and microstructure evolution during the flash sintering, the sample temperature is asymmetrically distributed along the current direction, and the internal grain boundary mobility in the sample is significantly improved. During this stage, electrochemical defects exert a significant impact on the microstructure. Based on the above researches, we developed ceramic flash joining technology by using phenomenon of low-temperature rapid mass transfer under electric field, and realized rapid joining between similar kind of ceramics/ceramics, ceramics/metals, and even dissimilar ceramics/ceramics. A new ultrafast ceramic synthesis technology by flash sintering was developed, which not only realized the rapid synthesis of typical oxide ceramics, but also realized the rapid synthesis of high entropy ceramics and oxide ceramics with eutectic morphology. An electroplastic forming technology of oxide ceramics was developed, and a rapid tensile and bending deformation of zirconia ceramics at low temperature and low stress was preliminarily realized. Finally, this review summarizes the challenges in the field of flash sintering mechanism, and looks forward to the development direction of flash sintering from two aspects of Joule heating effect and nonthermal effect, aiming to be beneficial to the development of flash sintering technology in China.

Lithium-sulfur (Li-S) batteries play a crucial role in the development of next-generation electrochemical energy storage technology due to its high energy density and low cost. However, their practical application is still hindered by the sluggish kinetics and low reversibility of the conversion reactions, which contribute to relatively low practical capacity, Coulombic inefficiency, and cycling instability. In this regard, the rational design of conductive, adsorptive and catalytic functional materials presents a critical pathway to stabilize and promote sulfur electrochemistry. Benefiting from the unique atomic and electronic structures of boron, boron-based materials exhibit multifarious and tunable physical, chemical and electrochemical properties, and have received extensive research attentions in Li-S batteries. This paper reviews the recent research progress of boron-based materials, including borophene, boron atom-doped carbon, metal borides and non-metal borides in Li-S batteries, concludes the remaining problems and proposes the future developing perspective.

Oxygen evolution reaction (OER) suffers from four-electron transfer, sluggish kinetics and high energy requirements, limiting the development of new energy technologies such as hydrogen production from water electrolysis. In recent years, non-noble metal composite catalysts have attracted increasing attention due to their advantages of excellent catalytic activity and cost compared with noble metal-based catalysts. This review summarizes the latest progress in this field. Firstly, the OER mechanism and the evaluation methods of catalytic performance are briefly introduced. Then the non-noble metal/nitrogen-doped carbon composites are further classified into metal/nitrogen-doped carbon composites, metal single atom/nitrogen-doped carbon composites, alloy/nitrogen-doped carbon composites, and metal oxide/nitrogen-doped carbon composites. The research progress of the electrocatalysts is summarized and analyzed based on the synthesis method and catalytic activity, aiming to explore the role of nitrogen-doped carbon materials in catalyst structure and catalyst performance. Finally, perspectives are given out for the current problems and future directions of non-noble metal/nitrogen-doped carbon composites.

Spontaneous coagulation casting (SCC) is a novel in-situ ceramic forming method, not only universal for various ceramics but also working well at room temperature in air. Here presents the finding of SCC, involving an anion dispersant which acts as both dispersing and coagulating agent. Then, the difference between SCC and other in-situ coagulation methods in principle was elucidated. In SCC, particles participate in the formation of organic network which originates from hydrophobic interaction and hydrogen bonding among the dispersant molecular chains. The ceramic gel formed by SCC is a physical gel and possesses low density which is conducive to water transportation and stress relaxation during drying. In contrast, the one by conventional gelcasting is a chemical gel in which particles are fixed by a dense organic network. Based on the hydrophobic interaction, this review focuses on the design and synthesis of a series of SCC agents to meet the demand of forming dense and porous ceramics from particles with different sizes. That is, an anion dispersant is hydrophobically modified by a surfactant with a short or long chain. The obtained two agents are used for preparation of dense and porous ceramics, respectively. Progress of key technologies in this area including ceramic joining without interface, construction of grain orientation, drying, preparation of dense ceramics and porous ceramics, by SCC is summarized. Typically, alumina disc with a diameter up to 1010 nm and alumina parts with complicated shape such as dome and guide are shown. Future development of SCC is also proposed to enable SCC is a more universal forming technology for advanced ceramics with a large and/or complicated dimension.

All-solid-state thin film lithium battery (TFLB) is regarded as the ideal power source for microelectronic devices. However, the relatively low ionic conductivity of amorphous solid-state electrolyte limits the improvement of electrochemical performance for TFLB. In this work, amorphous lithium silicon oxynitride (LiSiON) thin films are prepared by magnetron sputtering as solid-state electrolyte for TFLB. With optimized deposition condition, the LiSiON thin film exhibits a high ionic conductivity of 6.3×10^-6 S∙cm^-1 at room temperature and a wide voltage window over 5 V, making it a suitable thin film electrolyte for TFLB. A MoO₃/LiSiON/Li TFLB is constructed based on the LiSiON thin film electrolyte with large specific capacity (282 mAh∙g^-1 at 50 mA∙g^-1), good rate capability (50 mAh∙g^-1 at 800 mA∙g^-1), and acceptable cycle life (78.1% capacity retention after 200 cycles), demonstrating the feasibility of this electrolyte for practical applications.

Ceramics, with its excellent thermal, physical and chemical properties, have great potential applications in various fields, such as aerospace, energy, environmental protection and bio-medicine. With the development of relevant technology in these fields, the structural design of core components is increasingly complex, and the internal microstructures gradually become customized and gradient. However, the hard and brittle features of ceramics make it difficult to realize the forming of special-shaped parts by traditional manufacturing methods, which in turn limits further application. As a rapidly developing additive manufacturing technology, laser additive manufacturing technology presents a momentous advantage in the manufacturing process of extremely precision ceramic components: free molding without mold and support, quick response feature and short developing cycle, etc. At the same time, the technology can realize the flexible deployment of ceramic parts, which is expected to solve the problems mentioned above. Three kinds of powder-based laser additive manufacturing techniques of ceramic were reviewed in this paper: selective laser sintering and selective laser melting based on powder bed fusion technology; laser engineered net shaping based on direct energy deposition technology. The forming principle and characteristics were mainly discussed; the research progress of ceramic green body densification process in selective laser sintering technology and the forming principle, propagation mechanism and control methods of ceramic green body cracks in selective laser melting, and laser engineered net shaping technology were reviewed; the technical characteristics of selective laser sintering, selective laser melting and laser engineered net shaping technologies in shaping of ceramic parts were compared and analyzed; and the future development trends of laser additive manufacturing technology of ceramic parts were prospected.

The investigation of defects in perovskite crystals is essential to promote the development of perovskite solar cells. The defects result in non-radiative recombination as well as the deterioration of device stability. To reduce the impact of material defects on photovoltaic performance, it is necessary to deeply understand the types of perovskite film defects and the routes of suppression methods. According to electronic characteristics, defects can be divided into electron-rich and electron-deficient defects. Based on Lewis acid-base theory, electron-rich defects can be passivated by Lewis acid, and electron-deficient defects can be passivated by Lewis base or ionic liquids. These passivation additives can be added during the formation of perovskite film, or used to post-treat the surface of the films. This review summarized the defect passivation cases reported in recent years to visually present design strategies of additives and the effects of defect passivation on photovoltaic performance. Finally, developing multi-functional passivators, large-area passivation strategy and advanced charge transport layer were proposed for future perspective. This review is expected to promote the development of perovskite solar cells in the future.

Metal cyanamides/carbodiimides [M_x(NCN)_y], as oxygen/chalcogenide-like compounds, are a new class of inorganic functional materials. The quasi-linear [NCN]^2- anion endows their open and porous crystal structure, unique electronic structure and unique physicochemical properties. They have shown potential applications in many fields including solid-state luminescence, photo/electrocatalysis, and electrochemical energy storage, becoming a research hotspot in recent years. This review outlines the research history of metal cyanamides, introduces the crystal structures and physicochemical properties, summarizes their synthetic methods and strategies, and discusses the applications for electrochemical energy storage, focusing on the electrochemical performance and charge storage mechanism as new-type negative electrode materials for lithium/sodium ion batteries.

In the long river of human history, every technological revolution is accompanied by transition of cognition, development and utilization of energy. At present, China has become the No. 1 in the world in both production and consumption of energy, which continue rising in the excepted future. Developing energy technology is still a key way to solve the problems of excessive dependence on traditional fossil energy and environmental pollution, construct a reasonable social structure, promote the sustainable development of human society, and achieve the goals of carbon emission peaking and carbon neutrality. In 2020, renewable energy in China such as photovoltaics and wind power evolved marvelously which occupied 1/3 of global total volume. In this regard, energy materials are indispensable components, which play the core role in realizing conversion and utilization of clean energy, developing new energy technologies, and supporting the entire energy system.
In recent years, energy materials have achieved extensive and sustainable development in many fields, including secondary batteries, fuel cells, solar cells, supercapacitors, photoelectric catalysis, and energy-containing materials. For example, high nickel ternary materials as cathode material in the lithium-ion battery are leading the future of a new generation of automotive power battery technology towards faster charging speeds, longer service life and longer mileage^[1-4]. The ever increasing demand for energy storage has also spawned simultaneously a series of new battery technologies, such as lithium-sulfur^[5], lithium-air^[6] and solid-state batteries^[7]. They have advantages in energy density, economy and safety, but technical defects (e.g., shuttle effect in Li-S battery attributed to polysulfides, blockage of matrix pores in Li-air battery attributed to discharging product, unsatisfactory electrical conductivity of electrolyte in solid-state battery) are frustrating. Technological improvement and industrialization are strongly dependent on the innovative design and structural optimization of electrode and electrolyte materials. To promote the share of renewable energy in primary source, photovoltaics, the representative of new energy, received great expectation. In addition, halogen perovskite-based third-generation solar cell technology has achieved a solar energy conversion efficiency comparable to that of silicon single crystal, showing a prosperous photovoltaic industry in the future^[8]. However, its sensitivity to temperature, humidity, light, and oxygen^[9], and inevitable Pb-containing raw material in preparation still need to find a solution in the underlying materials design. Moreover, as continuously optimizing the traditional catalyst materials, like Pt and Pd, as well as the non-precious and non-metallic catalysts, the energy conversion efficiency of fuel cells has been gradually improved with reduction of their technical costs, meeting a certain degree of commercial application^[10-11]. Besides, photocatalytic and electrocatalytic technologies for CO₂ reduction and nitrogen fixation also provide a new way for the storage and utilization of renewable energy, technically support the carbon emission peak in 2030 and carbon neutrality in 2060^[12-13].
In the context of the era of sustainable development and the fiercely competitive international scientific and technological frontier research environment, in the energy materials research, including the exploration of physical and chemical properties, functional discovery, precise design and preparation of nanomaterials, and advanced device assembly, China has made many important breakthroughs. In order to focus on displaying the research results of Chinese scholars in this field, to promote academic exchanges among peers, and to stimulate interest in energy materials from all walks of life, Nanjing University of Science and Technology, Shanghai Institute of Ceramics, Huazhong University of Science and Technology, etc. hereby organize the publication of “Energy Materials Special Issue”, containing the latest research articles and reviews related to energy materials involved with perovskite photovoltaics, semitransparent solar cell, Li-ion battery, Mg battery, Li-S battery, thermoelectrics, CO₂ splitting, etc. It is hoped that this Special Issue can offer useful references for the scientific research and disciplinary development of energy materials in China.

Piezoelectric ceramic is a type of functional ceramic, which is able to convert the mechanical signal and the electronic signal mutually. Composed of piezoelectric ceramics and organic phase, piezoelectric composites have different kinds of connectivities, which not only determine the diverse applications of piezoelectric devices, but also promote the development of various shaping techniques in manufacturing piezoelectric materials and devices. In comparison with the traditional shaping methods, the most distinguishable advantage of additive manufacturing lies in its ability of quickly shaping a small batch of samples into geometrically complex designs without a mould, which makes it a highly suitable technique for investigating piezoelectric ceramics and its derivative devices in different kinds of connectivities. Meanwhile, the final additively manufactured samples require only tiny post-processing, have a high rate of utilization of the raw material and do not need cutting fluid during manufacturing. Due to the above-mentioned advantages, it attracts the widespread concerns from both academic and industrial communities. When focusing in the field of additive manufacturing ceramics, the data of scientific reports in additive manufacturing functional ceramics and devices prove that it is still in a growing period. In the perspective of different additive manufacturing techniques, this article discusses and compares additive manufacturing of both lead-free and lead-based piezoelectric ceramics in the aspects of their historical development of each technique, preparation of the raw materials, geometrical designs, measurement of functional properties, and applications of the printed samples, and forecasts the future development based on the current benefits and drawbacks of each additive manufacturing technique.

Special ceramics are widely used in aerospace, electronics, information, new energy, machinery, chemical industry, and other emerging industries. Their high temperature preparation process is still dominated by traditional gas kilns and electric heating furnaces with high carbon emissions and high energy consumption. The energy conservation-emission reduction situation is grim at present. Therefore, China is facing great pressure to achieve ‘double carbon’ goal, badly needing research and promotion of clean and efficient heating technology. Microwave heating uses the dielectric loss of the material itself to absorb microwave and convert electromagnetic energy into heat energy at molecular level. In this way, heat is generated simultaneously both inside and outside the whole material, leading the temperature gradient very low in the whole material. In addition to the volumetric heating, selective heating, power redistribution, thermal upheaval, and microwave plasma effect are important characteristics of microwave sintering. Microwave heating has the advantages of energy conservation, environmental protection, improved product performance and reduced combustion carbon emissions. There are many reports on microwave synthesis of various oxides, carbides, nitrides ceramic powders, and microwave sintering ceramic composites domestic and abroad. In this paper, the basic theories of microwave sintering and microwave mixed sintering are reviewed firstly, and then the latest research progress on preparation of ceramic powders by microwave heating and ceramic materials preparation by microwave sintering is introduced. Finally, microwave heating used in sintering of ceramic engineering products is introduced, which shows the superiority of microwave sintering. The key problems and the future development direction of special ceramics prepared by microwave sintering are also proposed.

With the development of nanomedicine, utilization of nanomaterials to catalyze the generation of excess reactive oxygen species (ROS) under exogenous ultrasound stimulation has attracted widespread attention for disease therapy, which is called sonodynamic therapy (SDT). Currently, development of high-efficiency sonosensitizers that can be used in SDT to improve ROS yield remains one of the most important challenges for current research and future clinical translation. Recently, benefited from the development of piezotronics and piezophototronics, novel sonosensitizers based on piezoelectric semiconductor nanomaterials have shown promising applications in SDT. In this review, we outline the structures and properties of piezoelectric semiconductors, and introduce the presumed mechanism of SDT with piezoelectric semiconductors. The newest research progresses on using piezoelectric semiconductor as sonosensitizer in cancer treatments and antibacterial applications are summarized. Finally, the existing challenges and future development trends in this field are proposed.

Magnesium metal batteries (MMBs) have attracted increasing attention due to the high volume specific capacity (3833 mAh/cm³) and high safety of Mg metal anode. Nevertheless, the high polarization effect induced by Mg²⁺ inhibits its diffusion in solid phase and therefore limits the specific capacity of MMBs. Li⁺/Mg²⁺ dual-salt electrolyte has been proposed to circumvent the sluggish diffusion of Mg²⁺ in solid phase, which enables Li⁺ to replace Mg²⁺ to drive the cathode reaction. In this work, the electrochemical performance of CoS₂ as conversion cathode of MMBs is studied based on different Li⁺/Mg²⁺ dual-salt electrolytes, and the effects of Li-salt concentration and discharge-charge voltage range on cycling stability are analyzed. The strategy of Li-salt additive remarkably promotes the conversion kinetics of CoS₂ based MMBs. By developing charge voltage to 2.75 V, the cycling stability of Mg-CoS₂ cell in LiCl-APC electrolyte is significantly enhanced. Its specific capacity can be maintained at 275 mAh/g after 150 cycles, which is much higher than that (33 mAh/g) under the protocol of 2.0 V charge voltage. It is found that the capacity degradation of MMBs is related to the irreversible reaction of CoS₂ and generation of Co₃S₄ at the charge potential of 2.0 V. And the dissolution of Co and S elements from active species aggravates the irreversible loss of capacity. This study provides an electrochemical activation solution to the development of transition metal sulfides in conversion type MMBs.

Two-dimensional (2D) materials have brought about significant technological advancements in the field of biomaterials. Transition metal carbides and/or nitrides (MXenes) have a planar structure educed from their corresponding parent MAX phase by selective etching of ‘A’ and further delamination. Since the first MXene was reported in 2011, MXenes now comprise a rapidly growing family of 2D materials, having attracted extensive attention from researchers. Owing to their excellent electronic properties, outstanding photothermal conversion performance, high specific surface area, good biocompatibility, and low toxicity, MXenes have shown a good application prospect in tumor theranostics. This paper reviews substantive findings of the original researches focused on the preparation, property and application in tumor theranotics, including recent advances, challenges and future perspectives of MXenes. Firstly, we briefly summarize the preparation methods and property of MXenes, including HF acid method, fluoride salt method, molten salt method, alkali-assisted hydrothermal method, and chemical vapor deposition method, as well as stability, mechanical, optical, and electrical properties. Secondly, we focus on the application of MXenes in photothermal therapy and combined therapy. The usual method is to combine photothermal therapy, photodynamic therapy and chemotherapy to carry out multi-modal combined treatment of tumors. The combined therapy can also be improved by constructing surface nanopores of MXenes and loading chemotherapy drugs in them. Furthermore, enhanced MXenes synergistic therapeutic effect on tumor and reduced toxic side effects on normal tissue can be endued by active targeting technology. In addition, the preparation of multifunctional MXenes composite nanomaterials to obtain radiation treatment and imaging capabilities such as computed tomography scans and magnetic resonance imaging, can establish an integrated platform for MXenes theranostics. Finally, we briefly introduced other applications of MXenes in biomedicine which are beneficial to tumor theranostics, and elaborate the current challenges and future development prospects of MXenes in cancer theranostics.

Potassium sodium niobate (K_0.5Na_0.5NbO₃, KNN) based ceramics can be widely used for pulsed power systems due to their fast charge-discharge rate, high transparency, wide range of working temperature, and long cycle life. Improving the electrical and optical property of KNN-based ceramics through modification is a research hotspot in this field. 0.825(K_0.5Na_0.5)NbO₃-0.175Sr_1-3x/2La_x(Sc_0.5Nb_0.5)O₃ (x=0, 0.1, 0.2, 0.3) (0.825KNN- 0.175SLSN) ceramics were synthesized by solid state method. The effect of La₂O₃ doping on the phase structure, microstructure, optical property, dielectric property, ferroelectric property and energy storage property of the ceramic was studied. The results indicated that the structure of 0.825KNN-0.175SLSN ceramics is pseudo-cubic phase with high symmetry. With increment of La₂O₃ content, the average grain size of 0.825KNN-0.175SLSN ceramics decreased, and the phase transition temperature (T_m) and saturation polarization intensity (P_max) increased and then decreased. 0.825KNN-0.175SLSN ceramics exhibit excellent transparency at x=0.3, the transmittance in the visible wavelength (780 nm) and near-infrared wavelength (1200 nm) ranges reaches 65.2% and 71.5%, respectively. The dielectric breakdown strength of 310 kV/cm and a recoverable energy density of 1.85 J/cm ³ are achieved at x=0.3.

As an important functional material, piezoelectric ceramics not only have the characteristics of high strength, high hardness, corrosion resistance, etc., but also can realize the mutual conversion between mechanical energy and electrical energy. Piezoelectric ceramics are widely used in sensors, drivers, capacitors and other piezoelectric parts, playing an important role in high-end equipment such as marine exploration, biomedicine, and electronic communications. The development requirements of intelligent, integrated, and lightweight piezoelectric functional devices in advanced technology fields have pushed their shape more and more complex. However, traditional fabricating processes, such as slip casting, injection molding, mould pressing, and machining, depend on molds or grinding tools. It is difficult to design and fabricate complex shape piezoelectric ceramics, especially with hollows and overhangs. Additive manufacturing technology can rapidly fabricate any complex structure parts based on the layer-by-layer fabricating principle with advantages of high molding efficiency and without molds. It can meet the needs of individualized, integration and complex manufacturing. In recent years, it has received extensive attention from researchers in the field of piezoelectric ceramics in both domestic and abroad. This article summarizes the main types of current additive manufacturing piezoelectric ceramics and their development status from the perspective of three raw material forms: powder, slurry and bulk materials, then comprehensively compares the characteristics of various processes. Application of additive manufacturing of piezoelectric ceramics in different fields has also been introduced. Finally, the challenges faced by additive manufacturing piezoelectric ceramics and the possible future development trends are summarized and prospected.

Oxygen reduction reaction (ORR) is important for energy and catalytic applications. Therefore, it is significant to develop highly active and selective catalysts to promote ORR. According to the reaction process, ORR can be categorized into two- and four-electrons transfer pathways. In this work, chemically modified graphene sheets with different defects were used as precursors, which were integrated with Ag-7,7,8,8-tetracyanoquinodimethane (Ag-TCNQ) to form hybrid catalysts. The ORR activities of Ag-TCNQ/high defect graphene and Ag-TCNQ/low defect graphene were compared. The results show that the electron transfer number of ORR with Ag-TCNQ/high defect graphene is 2.4. And its corresponding production yield of H₂O₂ is 0.62 mg/h, and Faraday efficiency is 64.45%. In comparison, the electron transfer number of ORR with Ag-TCNQ/low defect graphene is 3.7 and the corresponding half-wave potential is about 0.7 V (vs. RHE). Therefore, high structural defects promote the two-electron process of ORR, while low structural defects facilitate the four-electron process of ORR. In the composites, Ag-TCNQ nanoparticles and graphene have formed a hybrid effect to improve the catalytic activities.

Carbon-neutral fuel production by solar-driven two-step thermochemical carbon dioxide splitting provides an alternative to fossil fuels as well as mitigates global warming. The success of this technology relies on the advancements of redox materials. Despite the recognition of the entropic effect, usually energy descriptors (enthalpy of formation or energy of oxygen-vacancy formation) were used for computational assessment of material candidates. Here, in the first step, the criteria was derived based on the combination of solid-state change of entropy and formation enthalpy, and was used to thermodynamically assess the viability of material candidates. In the thermodynamic map, a triangular region, featuring large positive solid-state changes of entropy and small enough solid-state changes of formation enthalpy, was found for qualified candidates. Next, a first-principles DFT+U method was presented to fast and reasonably predict the solid-state changes of entropy and formation enthalpy of candidate redox materials, exemplified for pure and Samaria-doped ceria, so that new redox materials can be added to the thermodynamic map. All above results highlight the entropic contributions from polaron-defect vibrational entropy as well as ionic (oxygen vacancies) and electronic (polarons) configurational entropy.

Oxygen reduction reaction (ORR) is the key reaction in cathode for fuel cells. Because of the sluggish kinetics, platinum (Pt) is widely used as the electrocatalysts for ORR. However, the high cost of Pt and poor stability of carbon black support under high voltage limit the commercialization and durability of fuel cells. Two-dimensional transition metal dichalcogenides (2D TMDs) possess large specific area, tunable electronic structure, and high chemical stability, making them a good candidate for ORR catalysts with high activity and durability. This paper reviews the recent progress of 2D TMDs-based ORR electrocatalysts. First, crystal structure, electronic properties, and ORR reaction mechanism are briefly introduced. Then some strategies for adjusting ORR performance of 2D TMDs are summarized, including heteroatom doping, phase conversion, defect engineering, and strain engineering. Meanwhile, the ORR activity enhancement arising from 2D TMDs-based heterostructures is also analyzed. Finally, perspectives are given for current issues and their possible solutions.

At present, stereolithography 3D printing technology is widely used in ceramic additive manufacturing because of its high printing accuracy. Among them, the stereolithography ceramic slurry of non-oxide ceramics such as silicon carbide, silicon nitride, etc., has problems such as poor dispersion stability and low curing layer thickness because the incident light is difficult to penetrate and produce light curing reaction for printing high-solid-loading slurry. This is all because the refractive index and optical absorbance of the non-oxide ceramic printing material powder are relatively high. Therefore, printing and molding of high-solid-content non-oxide ceramics have become main challenges in stereolithography 3D printing, and the technology has attracted a large number of researchers to study its light-curing mechanism, powder control and other mechanisms. This paper systematically summarizes the research works of several non-oxide ceramics such as light-curing slurry preparation, light-curing molding, organic matter removal, and sintering densification. It also analyzes and discusses several methods of adjusting composition of photosensitive resin and modifying ceramic powder, and proposes innovative solutions to improve the slurry performance of non-oxide ceramics, optimize its light-curing printing, repair its densification defects and improve its performance. And the ultimate goal is to promote the advancement of high-precision preparation technology for light-curing additive manufacturing of large-size, complex-structure non-oxide ceramic parts.

Silicon carbide nanowires (SiCNWs) possess excellent electromagnetic absorption performance and a three-dimensional (3D) network structure is beneficial to the multiple reflection and absorption of electromagnetic waves (EMWs). The 3D staggered SiCNWs network preforms with a volume fraction of 20% was realized by vacuum filtration method. And then the PyC interphase and SiC matrix were prepared through chemical vapor infiltration (CVI) process, and the densified SiCNWs/SiC ceramic matrix composites were obtained through CVI and precursor impregnation pyrolysis (PIP) process. Methane (CH₄) and trichloromethylsilane (MTS) were selected as gaseous precursor of the PyC and SiC, respectively. With increase of deposited PyC from 0 to 29.5%, the electromagnetic interference (EMI) shielding efficiency (SE) of the porous SiCNWs increases from 9.2 dB to 64.1 dB in 8-12 GHz (X-band). The densified SiCNWs/SiC ceramic matrix composites with a mass gain of about 13% of PyC interphase present an average EMI SE of 37.8 dB in X-band. The achieved EMI shielding properties suggested that the potential application of the SiCNWs/SiC ceramic matrix composites may be a promising new-generation EMI shielding material.

Printable perovskite solar cells employ a device structure for which the organic-inorganic perovskite absorber is hosted by an inorganic mesoporous scaffold. Its advantages include simple fabrication process, low material cost and relatively high stability. However, it is challenging to homogeneously deposit high-quality perovskite crystals on the mesoporous scaffold. Herein, by incorporating lead acetate (Pb(Ac)₂) in the typical perovskite precursor, methylamine lead iodine (MAPbI₃), the crystal growth and pore-filling of the perovskite crystals in the mesoporous scaffold is improved by facilitating the crystal nucleation. Meanwhile, Ac^- and MA⁺ form MAAc which releases during thermal annealing process, resulting in excess PbI₂ in the perovskite layer which passivates the grain boundaries. By incorporating 1% molar ratio of Pb(Ac)₂ in the perovskite precursor, a power conversion efficiency of 15.42% is obtained for printable perovskite solar cells. This indicates that it is feasible to enhance the performance of printable perovskite solar cells by employing additives to tune the crystallization of the perovskite absorbers.

Ceramics are a series of inorganic nonmetallic materials with a long history and has been extensively used. They have been playing a vital role in the human civilization process. Nowadays, as one of the three pillars in the material systems for modern industry, ceramics with excellent physical and chemical properties have been increasingly used and researched and become indispensable in the high-tech application fields such as machinery and electronics, energy and environmental protection, aerospace and biomedical industries, especially for the advanced ceramics with complex and integrated structural and functional properties. However, due to their inherent high hardness and brittleness, when manufacturing ceramic products with highly complex three-dimensional shapes or customized structures and functions, the traditional molding and machining technologies often face certain technical limitations with great difficulty and long production cycle.
The emergence of additive manufacturing (AM) paves a new way to break through above limitations. AM technology is earliest known as freeform fabrication (FFF) or rapid prototyping (RP) technology, and was gradually popular with the general public and is now commonly known as 3D printing technology in this century. ‘Stereolithography (SL)’ photopolymerization additive manufacturing technology suitable for organic resin solutions and ‘Selective Laser Melting (SLM)’ additive manufacturing technology for metal powders, were invented in the US and Germany in the 1980s and 1990s, respectively. These two epoch-making technologies are the most significant representatives of all AM technologies. At present, over ten types of additive manufacturing technologies have been developed for various raw materials. However, compared with organic and metallic materials, ceramics generally possess lower physical and chemical activities and higher melting points; some AM processes used for organic and metallic materials cannot be directly applied to ceramic materials. Nevertheless, currently most of the ceramic AM technologies are derived from that made for organic and metallic materials. This makes the development of AM technologies for ceramic materials difficult, and thus its development history is relatively shorter. However, the magic and charm of AM lie in its unique flexibility of manufacturing highly complex shapes, as well as the advantages of customized structures and functions, which extensively attract worldwide researchers to investigate AM of ceramic materials and their applications.
In recent years, a number of excellent research groups and industrial organizations have sprung up in the field of ceramic AM. According to the statistics preliminary generated from the 1^st National Forum on Additive Manufacturing of Ceramics (FAME2021) initiated by Prof. CHEN Zhangwei of Shenzhen University in July 2021, there are approximately over 60 institutes in China specializing in the research of ceramic AM and applications, while more than 20 industrial manufacturers are involved in the development and fabrication of materials, printing process equipment, and post-processing equipment that are relevant to ceramic AM technology. Among them, the majority of research focuses on the AM of photopolymerization (including SL and Digital Light Processing (DLP)) or Direct Ink Writing (DIW) using the mixtures of ceramic powders and resins/adhesives. The rest mainly utilizes ceramic powders and high-power lasers such as Selective Laser Sintering (SLS), Laser Directed Energy Deposition (LDED), and other processes for direct AM of ceramics. In terms of the types of ceramic materials involved, most research focuses on oxide ceramic materials, such as SiO₂, ZrO₂, Al₂O₃, and their mixed or multiphase materials, as well as PZT, BTO, TCP, and other advanced ceramics. The main application directions include load-bearing components and functional parts, such as catalytic carriers, casting molds, heat insulation, piezoelectric, sensors, artificial bones, dentistry, ultra-high temperature parts, optics, and other fields. Besides, in recent years, researchers have also turned to AM of non-oxide ceramics such as SiC, Si₃N₄, AlN, and even more complex Polymer-Derived Ceramics (PDCs) that generate polynary ceramics, and substantial progress has been achieved.
In general, the ceramic AM processes take ceramic-based materials as ‘inks’ and focused energies such as light energy, mechanical energy and heat energy as ‘pens’, to ‘draw’ a variety of complex ceramic devices with integrated structures and functions, which is similar with the Chinese fairy tale of ‘Ma Liang the Magic Brush’. It is noteworthy that the outcome of ‘Ma Liang the Magic Brush’ was ‘What You Draw Is What You Get’. In our opinion, this is exactly the ultimate goal of AM or 3D printing, namely ‘What You Print Is What You Get’. There are still numerous challenges to overcome to achieve ‘What You Print Is What You Get’ in the field of ceramic AM. Due to the complicated material properties of ceramics, the process of shaping by various AM technologies involves the preparation of the material feedstock systems, the adaptation of forming process, and the optimization of heat treatment and post-treatment process. Therefore, material selection and controls over the forming process, deformation and defect, structures and properties, and other aspects require overall investigation and careful balance.
In the second half of 2021, while the conference of FAME2021 was held, the Editorial Board of the Journal of Inorganic Materials invited Prof. LU Jian from the City University of Hong Kong (CUHK) and Prof. CHEN Zhangwei from Shenzhen University (SZU) as guest editors to organize this Special Issue (SI) themed ‘Additive Manufacturing of Inorganic Materials’. Prof. WU Jiamin from Huazhong University of Science and Technology (HUST) also contributed to the organization of the SI. This SI focuses on some of the latest research outcomes and review articles in the field of ceramic AM in China, representing the frontier progress of ceramic AM research in China. Due to the limitations of time and space, some excellent work cannot be included in this SI in a timely manner. We hope that the SI can provide a useful reference for promoting the research and application development of ceramic AM in China. With ceramics as inks and focused energies as pens, would ceramic AM mark the new chapter like ‘Ma Liang the Magic Brush’, manifesting a significant leap from the processing and engineering research of ‘Accumulating sands to form a pagoda’ to the popularized application of high added value of ‘Turning stones into gold by touching’? We believe that with the unremitting efforts and progress made by researchers worldwide, this dream will eventually come true in the near future!

Development and application of power lithium-ion batteries are strictly restricted by their high temperature and high voltage performance, such as capacity degradation and gas swelling, which are related to not only the modified electrode material and battery design but also the electrolyte. Herein, tetravinylsilane (TVS) was applied as electrolyte additive to improve storage and cycling performances of LiNi_0.6Co_0.2Mn_0.2O₂ (NCM622)/graphite pouch cell at high cutoff voltage (4.4 V) and high temperature (45-60 ℃). The capacity retention rate of the cell after 400 cycles (2.8-4.4 V) at 1C (1C=1.1 Ah) with mass fraction 0.5% TVS in the electrolyte is as high as 92%, compared with 82% for its counterpart without TVS. On the one hand, TVS is preferentially oxidized under high voltage, contributing to the formation of a high-temperature resistant CEI (cathode electrolyte interphase) film on the surface of NCM622 particles, which effectively inhibits generation of internal cracks in NCM622 particles and dissolution of transition metal ions. On the other hand, TVS can also be preferentially reduced and polymerized, thus forming a stable SEI film on the surface of graphite anode, which inhibits the side reaction between the electrolyte and the negative electrode.

The robust development of clinical medicine and biomaterials boosts diagnostic imaging, effective treatment, and precise theranostics in various diseases. The emerging interdiscipline of materials and medicine, termed as materdicine, aims to surmount the critical obstacles and challenges faced by traditional medicine, such as systemic toxicity, poor bioavailability, inferior site-targeting specificity, and unsatisfied diagnostic/therapeutic efficacy. Herein, the state-of-the-art advances regarding the applications of diverse medmaterials for disease diagnosis, therapy, and theranostics are systematically summarized in this review, especially focusing on the nanoscale medmaterials. We firstly emphasize and discuss biomedical imaging (e.g., optical imaging, magnetic resonance imaging, ultrasound imaging, computed tomography imaging) and therapeutic strategies (e.g., photothermal therapy, dynamic therapy, immunotherapy, synergistic therapy) in the field of cancer treatment. Furthermore, we highlight the important progress of medmaterials in the diagnosis and treatment of other kinds of diseases including orthopedic diseases, respiratory system, and brain diseases. Especially, the elaborated medmaterials for other representative biomedical applications, such as biosensing and antibacteria, are illustrated in detail. Finally, we discuss the current challenges and future opportunities for the practical application of these unique medmaterials in materdicine for accelerating their early realization of clinical translations, promoting the progresses of clinical medicine and benefiting the patients.

Graphitic carbon nitride (g-C₃N₄) is widely used in the field of photocatalysis due to its unique two-dimensional planar structure and suitable energy band structure. However, it has some disadvantages such as fast recombination of the electron-hole, low visible-light utilization efficiency and poor dispersion in water, which hinder its application. In this study, the hydrogel prepared by sodium alginate was used as matrix to improve the dispersion of Ag@C₃N₄ composite in water, and at the same time enhanced the separation efficiency of photoelectron-holes pairs, thus improving its photocatalytic performance. Firstly, g-C₃N₄ was synthesized by thermal polymerization and then exfoliated into nanosheets by ultrasound. Then, Ag nanoparticles were deposited in situ on the surface of g-C₃N₄ by solution method to prepare Ag@C₃N₄. Finally, hydrogel loaded with Ag@C₃N₄ (SA/Ag@C₃N₄) was obtained by using calcium ion as crosslinker and sodium alginate (SA) as precursor. The morphology, microstructure and phase composition of the as-prepared photocatalyst were characterized. The as-prepared SA/Ag@C₃N₄ exhibited a 1.5 times higher photocatalytic degradation rate of methyl orange than that of Ag@C₃N₄. The catalytic mechanism was investigated by photoluminescence spectrum, time resolved photoluminescence spectrum and electron paramagnetic resonance spectrum. The results showed that the surface plasmon resonance effect of silver nanoparticles together with the porous structure and mass transfer channel of sodium alginate hydrogel plays a synergistic role in the enhancement of photocatalytic performance.

The electrocaloric effect refers to the phenomenon of the temperature change of a material caused by the application or removal of an electric field, and includes two types, positive electrocaloric effect and negative electrocaloric effect. As a high-efficiency, noise-free and environment-friendly refrigeration effect, the electrocaloric effect shows promising application in the field of solid-state refrigeration, especially in integrated circuit refrigeration, and has attracted extensive research interests over the past decades. It is reported that the cooling capacity of the electrocaloric effect can be significantly improved by combining the positive and negative electrocaloric effects. However, different from the widely studied positive electrocaloric effect, the research on negative electrocaloric effect is relatively rare due to its complex physical origin. This article focuses on the latest research progress of the negative electrocaloric effect in antiferroelectric materials. The specific content includes the following four parts. Firstly, starting from the research history of the electrocaloric effect, the principle of refrigeration of the electrocaloric effect is introduced, as well as a typical dual refrigeration cycle that can combine positive and negative electrocaloric effect. Secondly, the indirect measurement method of negative electrocaloric effect based on Maxwell relationship, and several direct measurement methods of negative electrocaloric effect, and the suitable applying conditions as well as the advantages and disadvantages of different methods are discussed. Thirdly, taking antiferroelectric which is a typical negative electrocaloric effect materials as an example, the physical origin of negative electrocaloric effect is narrated. Then the recent progress of negative electrocaloric effect in the antiferroelectric film and antiferroelectric bulk materials is reviewed. In addition, the negative electrocaloric effect in some other ferroelectric materials is also briefly introduced. Finally, a summary and prospect of the research on the negative electrocaloric effect are put forward.

Two-dimensional transition metal dichalcogenides are appealing materials for the preparation of nanoelectronic devices, and the development of memristors for information storage and neuromorphic computing using such materials is of particular interest. However, memristor arrays based on two-dimensional transition metal dichalcogenides are rarely reported due to low yield and high device-to-device variability. Herein, the 2D MoTe₂ film was prepared by the chemical vapor deposition method. Then the memristive devices based on 2D MoTe₂ film were fabricated through the polymethyl methacrylate transfer method and the lift-off process. The as-prepared MoTe₂ devices perform stable bipolar resistive switching, including superior retention characteristics (>500 s), fast switching (~60 ns for SET and ~280 ns for RESET), and excellent endurance (>2000 cycles). More importantly, the MoTe₂ devices exhibit high yield (96%), low cycle-to-cycle variability (6.6% for SET and 5.2% for RESET), and low device-to-device variability (19.9% for SET and 15.6% for RESET). In addition, a 3×3 memristor array with 1R scheme is successfully demonstrated based on 2D MoTe₂ film. And, high recognition accuracy (91.3%) is realized by simulation in the artificial neural network with the MoTe₂ devices working as synapses. It is found that the formation/rupture of metallic filaments is the dominating switching mechanism based on the investigations of the electron transport characteristics of high and low resistance states in the present MoTe₂ devices. This work demonstrates that large-scale two-dimensional transition metal dichalcogenides film is of great potential for future applications in neuromorphic computing.

Sulfurized pyrolyzed poly(acrylonitrile) (S@pPAN) composite as cathode material of Li-S battery realizes a solid-solid conversion reaction mechanism without dissolution of polysulfides. However, its surface and interface characteristics influence the electrochemical performance significantly, and there are also obvious volume changes during electrochemical cycling. In this study, single-walled carbon nanotubes (SWCNT) and sodium carboxymethyl cellulose (CMC) were used as binder for S@pPAN cathode to regulate the surface of S@pPAN and alleviate volume changes during charging and discharging. At a current density of 2C, capacity retention rate of the batteries after 140 cycles was 84.7%, and a high specific capacity of 1147 mAh∙g^-1 can still be maintained at a high current density of 7C. The ultimate tensile strength for the film of the composite binder increases by 41 times after adding SWCNT, and the composite binder guarantees a more stable electrode interface during operation, thereby effectively improves the cycle stability of the as sembled lithium-sulfur batteries.

Poor toughness and high synthesis pressure of binderless cBN limits its application in the field of cutting tool. To enhance its toughness, an advanced layered BN toughened cBN (Lt-cBN) bulk was developed under industrial pressure. Then, the cutting performance and wear resistance of Lt-cBN was analyzed based on the unique microstructure during tungsten carbide cutting. It is found that the Lt-cBN reaches a high fracture toughness of 8.5 MPa·m^1/2, and is capable of realizing ultra-precision cutting of tungsten carbide with smooth surface of roughness lower than R_a 10 nm. The layered BN at the intersection of cBN grains within Lt-cBN contributes to the enhanced toughness, which further slows down the transformation of amorphization as well as the wear rate of the surface layer. Thus Lt-cBN exhibits better cutting performance and wear resistance in contrast to commercial binderless pure cBN material. The wear of Lt-cBN can be explained by the soft partially amorphous layer formed on the flank surface being rubbed and continuously removed in the form of abrasive wear.

BaTiO₃ has a wide range of applications in microelectromechanical systems and integrated circuits due to its excellent dielectric, ferroelectric, piezoelectric, and pyroelectric properties. For the applied research and device applications of BaTiO₃ films, reducing its deposition temperature to be compatible with the CMOS-Si technology is an important Challenge. Here, with the help of a LaNiO₃ buffer layer which has a closely-matched lattice with BaTiO₃, (001)-textured BaTiO₃ films were sputter-deposited at 450 ℃ on single crystalline Si(100) substrates, which consisting of well-cryotallized, evenly-distributed columnar nanograins with an average grain size of 27 nm. Our result showed that this deposition temperature can maintain the columnar nanograin structure with a relatively large grain size, leading to a good ferroelectric performance. In addition, a small residual strain on Si was also helpful to improve its ferroelectric and dielectric properties. The remnant polarization and saturated polarization of these BaTiO₃ films reached 7 and 43 μC·cm^-2, respectively, while leakage current densities were as low as 10^-5 A·cm^-2 at an applied electric field of 0.8 MV·cm^-1. These BaTiO₃ films also displayed excellent frequency stability with a low dielectric loss in which relative dielectric constant measured to be ~155 at 1 kHz, slightly being reduced to ~145 after increasing the frequency to 1 MHz. Meanwhile, the dielectric loss slightly increased from 0.01 at 1 kHz to 0.03 at 1 MHz. Lastly, through capacitance-voltage (C-V) tests, these films exhibited a large dielectric tunability of~51% and a figure of merit (FOM) of ~17 (@1 MHz). These films have a good potential for applications in tunable dielectrics.

Graphene has played a major role in wearable electronic textiles due to its excellent electrical conductivity, superior flexibility and environmental stability. In this work, a green-yellow reversible electrothermochromic fabric was constructed via a facial double side coating. The self-made graphene paste is coated on the surface of polyester fabric by screen printing technology. The hybrid thermochromic ink with reversible color-changing property is coated on the opposite side of the graphene layer by screen printing technology. Structural properties and discoloration principle of the fabric were analyzed. Their thermal and color-changing properties were studied by using infrared thermal imaging and colorimeter. The results show that the graphene forms a conductive layer with a thickness of 250 μm that allows Joule heating to supply the thermal resource for the electrothermochromic behavior. This fabric changes from green to yellow with a gradual heating that exceeded 45 ℃ at 12 V due to the ring closure and opening of crystal violet lactone. Its color change response time is about 15 s, while fading response time is about 27 s. The electro-thermochromic fabric is not disturbed once undergoing a bending angle range from 30° to 180° and the voltage-current curve remains stable. Performance of the fabric does not significantly degrade after 200 heating/cooling continuous cycles. In conclusion, a sensitive electro-thermochromic fabric with good cycle performance from green to yellow with the structure of graphene film‖polyester fabric‖thermochromic film is successfully prepared, which has a high application potential in the fields of military camouflage and wearable display.

As green rechargeable batteries, lithium-ion batteries feature high energy and power density. However, commonly-used electrolytes, organic compounds, in commercially available lithium-ion batteries are flammable and toxic, which leaves them at the risk of combustion and explosion when being overcharged or short-circuited. In order to solve this problem, much attention has been paid to lithium-ion batteries with aqueous electrolytes, which take low-toxicity and high safety as the prominent advantages. The working voltage, 1.5-2.0 V, indicates their usage mainly in the field of energy storage. Considering the hydrogen and oxygen evolution, conventional anode materials used in commercially available lithium-ion batteries are inconformity for water-based lithium-ion batteries. Therefore, the key to the development of aqueous lithium-ion batteries lies in the selection of anodes. The anode material, LiTi₂(PO₄)₃, has drawn the attention of researchers due to its advantages such as three-dimensional channel, and appropriate lithium-ion intercalation potential. The synthesis methods of LiTi₂(PO₄)₃ mainly include high temperature solid-phase calcination, Sol-Gel methods and hydrothermal reaction, etc. To further improve the electrochemical performance of LiTi₂(PO₄)₃, strategies can be used such as particle nanocrystallization, morphology control, element doping, and carbon-coating, etc. This review focuses on the synthesis and modification of LiTi₂(PO₄)₃, as well as related research progress. At last, the future development of LiTi₂(PO₄)₃ as anode material for lithium-ion battery is properly prospected.

Because of low thermal conductivity and weak physical and chemical stabilities, traditional “phosphor in silicone” color converters are precluded from high-power white LED applications. All-inorganic bulk luminescence materials not only can circumvent organic encapsulation, but also have higher thermal conductivity. However, those bulk materials are high in cost and very difficult to be shaped into three-dimensional structures. Here, based on amorphous silica nanoparticles, a slurry, containing (Gd,Y)AG:Ce phosphor powders and can be polymerized under UV light, were developed. Bulk (Gd,Y)AG:Ce-silica glass composites were prepared successfully through photo curing, debinding in air and pressureless sintering. Under excitation of blue light, these luminescence glass-ceramics exhibit broadband orange emission peaking at 575 nm with internal quantum efficiency higher than 90%. Our results show that the interfacial reaction between (Gd,Y)AG:Ce and silica glass is very weak, and thus the former can be well embedded into bulk silica glass. Such all-inorganic color converters were further used to fabricate high-power warm white LEDs with correlated color temperature smaller than 4500 K, color rendering index higher than 75, and luminous efficiency of 74 lm·W ^-1. Luminescence saturation threshold of the as-fabricated laser lighting device is as high as 2.84 W·mm^-2, where its luminous flux can achieve 180 lm. Moreover, preparation of (Gd,Y)AG: Ce-silica glass composites is compatible to 3D printing technology, thus allowing the mass manufacturing of color converters with complex 3D structures, which may promote personalization and modularization of high-power white LEDs.

MnTe is a promising candidate for the p-type lead-free thermoelectric material in middle temperature application. However, its thermoelectric performance isn’t qualified for some conventional n-type materials to form efficient thermoelectric devices. In this study, Mn_1.06-xGe_xTe (x=0, 0.01, 0.02, 0.03, 0.04) polycrystalline block samples with different Ge doping contents were efficiently synthesized by vacuum melting quenching and spark plasma sintering. The as-obtained Mn_1.06-xGe_xTe bulk was dense and consisted of homogeneous composition. Tiny extensive Mn can effectively restrict the formation of the second phase of MnTe₂ and improve the thermoelectric properties of the matrix phase. Electrical conductivity of the materials increasing to 7×10³ S∙cm^-1 results from the enhanced carrier concentration 7.328×10¹⁸ cm^-3 at 873 K, which contributed to a power factor of 620 μW∙m^-1∙K^-2 by 4% Ge doping. Meanwhile, Mn_1.06-xGe_xTe showed the reduced thermal conductivity of 0.62 W∙m^-1∙K^-1 by enhanced phonons scattering intensified with point defects, realizing the effective regulation of both electrical- and thermal-transport properties. Mn_1.02Ge_0.04Te achieved a thermoelectric performance of 0.86 at 873 K, which evolved by 43% compared with the pristine sample.

Porous design of SiC composites with lightweight, high strength and low thermal conductivity can be obtained by constructing porous silicon carbide nanowires (SiCNWs) network and controlling chemical vapor infiltration (CVI) process. The SiCNWs network with an optimized volume fraction (15.6%) and uniform pore structure was prepared by mixing SiCNWs and polyvinyl alcohol (PVA) firstly. SiCNWs reinforced porous SiC ceramic matrix composite (SiCNWs/SiC) with a small uniform pore can be obtained by controlling the CVI parameters. The morphology of the grown SiC matrix, from the spherical particles to the hexagonal pyramid particles, can be influenced by the CVI parameters, such as temperature and reactive gas concentration. The strength of the SiCNWs/SiC ceramic matrix composites reaches (194.3±21.3) MPa with a porosity of 38.9% and thermal conductivity of (1.9± 0.1) W/(m·K), which shows the toughening effect and low thermal conductivity design.

Na-ion batteries, which currently use flammable and explosive organic electrolytes, now urgently need to develop high performance sodium ion solid electrolyte to realize more safe and practical application. Na₃Zr₂Si₂PO₁₂ is one of the most promising solid sodium electrolytes for its wide electrochemical window, high mechanical strength, superior air stability and high ionic conductivity. But its inhomogeneous mixing of the ceramic particles with the binders causing much more pores in the green bodies makes it difficult to obtain high-density and high-conductivity ceramic electrolytes after sintering. Herein, the spray drying method was used to enable Na₃Zr₂Si₂PO₁₂ particles uniformly coated with binders and granulated into spherical secondary ones. The as-prepared normal distributed particles can effectively contact each other and reduce porosity of ceramic green body. After sintering, Na₃Zr₂Si₂PO₁₂ ceramic pellets via the spray drying show relative density of 97.5% and ionic conductivity of 6.96×10^-4 S∙cm^-1 at room temperature. In contrast, the relative density and room-temperature ionic-conductivity of Na₃Zr₂Si₂PO₁₂ ceramic pellets prepared without the spray-drying are only 88.1% and 4.94×10^-4 S∙cm^-1, respectively.

Semitransparent photovoltaics (STPV) is a promising solar energy harvesting technology because it can be integrated to harness huge sun-facing areas of modern buildings for electricity generation. Its thermodynamic efficiency limits are of fundamental interest. This work extended the analyses from neutral STPV for building windows to those installed on the surface of colored building envelops according to the principle of detailed balance. Results show that the efficiency limit of STPV for blue building envelops is as high as 28.3%, which represents a 10% absolute enhancement compared to the neutral STPV for building windows (18.1%). These results demonstrate that STPV can be integrated into both windows and envelops of modern buildings, which has the potential to offset the low density of solar energy. This work provides guidelines on the selection and the development of active materials for STPV.