In 2004, Yeh and Cantor introduced high-entropy alloys (HEAs), which maximize configurational entropy by utilizing nearly equal elemental molar ratios. These HEAs are valuable for exploring the central regions of phase diagrams. Building on this concept, Rost et al. proposed entropy-stabilized oxides in 2015, revealing that high-entropy oxides (HEOs) exhibit structural stability driven by entropy. This article provides a comprehensive overview of HEOs, with a specific focus on high-entropy oxide ceramics (HEOCs). The paper explores the origins of the high-entropy concept and the fundamental effects of high-entropy materials. It examines entropy from its basic definition and investigates microscopic atomic distribution, crystal-level distortions, and electronic structures. Additionally, the article introduces theoretical prediction methods applied to high-entropy materials. Furthermore, this review systematically summarizes HEOCs, encompassing three key aspects: crystal structure, preparation methods, and performance applications. Finally, the review concludes by proposing future research directions based on the current progress in HEOCs.

As electromagnetic technology advances and demand for electronic devices grows, concerns about electromagnetic pollution intensify. This has spurred focused research on innovative electromagnetic absorbers, particularly chalcogenides, noted for their superior absorption capabilities. In this study, we successfully synthesize 3R–TaS2 nanosheets using a straightforward calcination method for the first time. These nanosheets exhibit significant absorption capabilities in both the C-band (4–8 ​GHz) and Ku-band (12–18 ​GHz) frequency ranges. By optimizing the calcination process, the complex permittivity of TaS2 is enhanced, specifically for those synthesized at 1000 ​°C for 24 ​h. The nanosheets possess dual-band absorption properties, with a notable minimum reflection loss (RLmin) of −41.4 ​dB in the C-band, and an average absorption intensity exceeding 10 ​dB in C- and Ku-bands, in the absorbers with a thickness of 5.6 ​mm. Additionally, the 3R–TaS2 nanosheets are demonstrated to have an effective absorption bandwidth of 5.04 ​GHz (3.84–8.88 ​GHz) in the absorbers with thicknesses of 3.5–5.5 ​mm. The results highlight the multiple reflection effects in 3R–TaS2 as caused by their stacked structures, which could be promising low-frequency absorbers.

Zinc-ion hybrid supercapacitors (ZHSCs) have been widely considered as promising candidates for flexible electrochemical energy storage devices. The key challenge is to develop hydrogel electrolytes with high hydrophilicity, anti-freezing, bending resistance, and stable interface with electrodes. This study reported a hydrogel electrolyte system that can meet the above functions, in which the zincophilic and negatively charged SO3−, migratable Na+, abundant hydrophilic functional groups, gum xanthan, and porous architecture could effectively promote the electrochemical performance of ZHSCs. ZHSCs with such hydrogel electrolytes not only exhibited good low-temperature performance but also showed excellent bending resistance ability. A high specific capacitance could be kept after a long air-working lifespan over 10,000 cycles under a wide operation voltage of 1.85 V at −10 °C. Furthermore, flexible ZHSCs could maintain the capacitance retention of 93.18% even after continuous 500 bends at an angle of 180°. The designed hydrogel electrolytes could be also used for other electrochemical energy storage devices with anti-freezing and bending resistance by changing electrolyte salt.

The synthesis of carbon supporter/nanoscale high-entropy alloys（HEAs） electromagnetic response composites by carbothermal shock method has been identified as an advanced strategy for the collaborative competition engineering of conductive/dielectric genes. Electron migration modes within HEAs as manipulated by the electronegativity, valence electron configurations and molar proportions of constituent elements determine the steady state and efficiency of equivalent dipoles. Herein, enlightened by skin-like effect, a reformative carbothermal shock method using carbonized cellulose paper（CCP） as carbon supporter is used to preserve the oxygen-containing functional groups（O·） of carbonized cellulose fibers（CCF）. Nucleation of HEAs and construction of emblematic shell-core CCF/HEAs heterointerfaces are inextricably linked to carbon metabolism induced by O·. Meanwhile, the electron migration mode of switchable electronrich sites promotes the orientation polarization of anisotropic equivalent dipoles. By virtue of the reinforcement strategy, CCP/HEAs composite prepared by 35% molar ratio of Mn element(CCP/HEAs-Mn 2.15 ) achieves efficient electromagnetic wave（EMW） absorption of-51.35 d B at an ultra-thin thickness of 1.03 mm. The mechanisms of the resulting dielectric properties of HEAs-based EMW absorbing materials are elucidated by combining theoretical calculations with experimental characterizations, which provide theoretical bases and feasible strategies for the simulation and practical application of electromagnetic functional devices（e.g., ultra-wideband bandpass filter）.

Recent advances in two-dimensional bifunctional electrocatalysts for full water splitting are systematically reviewed, discussing challenges and opportunities for further research.

Metallic zinc is an ideal anode material for aqueous rechargeable zinc-ion batteries (ZIBs) owing to its high ca-pacity in theory, low redox potential, high security and low cost. However, metallic zinc anodes suffer from an inferior long-term cycling stability, due to zinc dendrite growth, zinc corrosion and other factors. Elucidat-ing potential reasons for these issues is desperately needed for large-scale applications of metallic zinc anodes. Herein, we aim to parse zinc stripping/plating behaviors and dendrite growth in various aqueous electrolytes and explore the mechanism of failure process of metallic zinc electrodes by combining an operando transmis-sion electron microscope (TEM) technique, electrochemical analysis and theoretical calculation. Besides, effects and acting mechanism of Mn2+ and CF3SO(3)- in zinc-salt aqueous electrolytes on zinc plating/stripping behavior were investigated. The results demonstrated that adding Mn2+ could suppressed zinc dendrite growth by forming manganese-based compounds clusters around zinc electrodes during zinc plating process. In addition, dendrite-free anode was garnered when Zn(CF3SO3)(2) was employed as electrolyte, enabling the superior stability and excellent reversibility of Zn/Zn symmetric cell. This work not only reports a deep understanding of zinc strip-ping/plating behaviors in aqueous electrolytes, but also provides effective strategies to achieve long-term stable zinc anodes and ZIBs.

Nano-copper modified three-dimensional zinc mesh(nano Cu@3D Zn mesh,denoted as 3D Cu-Zn) electrode was designed and fabricated. The 3D Cu-Zn electrode was adopted as the host material of Zn deposition in zinc ion batteries. Stable Zn anode with long cycle life was achieved. The 3D Cu-Zn electrode with 3D zinc mesh skeleton and uniformly distributed Cu nanoparticles with 3D dendritic morphology can reduce the local current density and provide structural support and accommodation space for Zn deposition. In addition,the copper with strong zinc binding ability on the surface of the zinc mesh and subsequent in situ formed Cu-Zn alloy can effectively reduce the nucleation overpotential and act as uniformly distributed nucleation sites to guide the uniform nucleation and deposition of zinc. The 3D Cu-Zn electrode exhibits low nucleation overpotential and interfacial impedance,and shows excellent cycling stability(over 1100 h lifespan)in symmetric cells at a current density of 0.5 mA/cm(2). When combined with MnO2 cathode,the full cell with 3D Cu-Zn electrode exhibits smaller polarization,superior rate performance and excellent cycling performance.

Nano-copper modified three-dimensional zinc mesh(nano Cu@3D Zn mesh,denoted as 3D Cu-Zn) electrode was designed and fabricated. The 3D Cu-Zn electrode was adopted as the host material of Zn deposition in zinc ion batteries. Stable Zn anode with long cycle life was achieved. The 3D Cu-Zn electrode with 3D zinc mesh skeleton and uniformly distributed Cu nanoparticles with 3D dendritic morphology can reduce the local current density and provide structural support and accommodation space for Zn deposition. In addition,the copper with strong zinc binding ability on the surface of the zinc mesh and subsequent in situ formed Cu-Zn alloy can effectively reduce the nucleation overpotential and act as uniformly distributed nucleation sites to guide the uniform nucleation and deposition of zinc. The 3D Cu-Zn electrode exhibits low nucleation overpotential and interfacial impedance,and shows excellent cycling stability(over 1100 h lifespan)in symmetric cells at a current density of 0.5 mA/cm(2). When combined with MnO2 cathode,the full cell with 3D Cu-Zn electrode exhibits smaller polarization,superior rate performance and excellent cycling performance.

Zinc-ion batteries (ZIBs) have garnered considerable interest due to their inherent high safety, low cost, and environmental friendliness. However, the reaction mechanism of cathode material in ZIBs is not entirely clear. Herein, Mixed-phase MoS(2 )with a high proportion (66%) of 1T phase and 2H phase (TH-MoS2), synthesized by the hydrothermal method, is reported as the cathode material for ZIBs. Material characterizations show that THMoS2 have obvious two phase MoS2 with different crystal structures causes sulfur vacancies, increases interlayer spacing and intercalation water. TH-MoS2 cathode delivers excellent electrochemical performance, a satisfactory capacity of 156 mAh g(-1) , and an excellent cycling performance with 97.3% capacity retention after 500 cycles at 1 A g(-1). The ex-situ characterizations elucidate that TH-MoS2 achieves highly reversible Zn2+ storage with negligible phase transition, volume change, and lattice distortion upon cycle. Based on kinetic analysis and first principles calculations results, Zn2+ and H+ can be stored in TH-MoS2 and the energy storage mechanism of THMoS2 electrode is dominated by pseudocapacitance. Understanding the MoS2 reaction mechanism will facilitate comprehension of cathode materials for ZIBs.

Nano-copper modified three-dimensional zinc mesh(nano Cu@3D Zn mesh,denoted as 3D Cu-Zn) electrode was designed and fabricated. The 3D Cu-Zn electrode was adopted as the host material of Zn deposition in zinc ion batteries. Stable Zn anode with long cycle life was achieved. The 3D Cu-Zn electrode with 3D zinc mesh skeleton and uniformly distributed Cu nanoparticles with 3D dendritic morphology can reduce the local current density and provide structural support and accommodation space for Zn deposition. In addition,the copper with strong zinc binding ability on the surface of the zinc mesh and subsequent in situ formed Cu-Zn alloy can effectively reduce the nucleation overpotential and act as uniformly distributed nucleation sites to guide the uniform nucleation and deposition of zinc. The 3D Cu-Zn electrode exhibits low nucleation overpotential and interfacial impedance,and shows excellent cycling stability(over 1100 h lifespan)in symmetric cells at a current density of 0.5 mA/cm(2). When combined with MnO2 cathode,the full cell with 3D Cu-Zn electrode exhibits smaller polarization,superior rate performance and excellent cycling performance.

A booming demand for wearable electronic devices urges the development of multifunctional smart fabrics. However, it is still facing a challenge to fabricate multifunctional smart fabrics with satisfactory mechanical property, excellent Joule heating performance, highly efficient photothermal conversion, outstanding electromagnetic shielding effectiveness, and superior anti-bacterial capability. Here, a MoSe2 @MXene heterostructure-based multifunctional cellulose fabric is fabricated by depositing MXene nanosheets onto cellulose fabric followed by a facile hydrothermal method to grow MoSe2 nanoflakes on MXene layers. A low-voltage Joule heating therapy platform with rapid Joule heating response (up to 230 °C in 25 s at a supplied voltage of 4 V) and stable performance under repeated bending cycles (up to 1000 cycles) is realized. Besides, the multifunctional fabric also exhibits excellent photothermal performance (up to 130 °C upon irradiation for 25 s with a light intensity of 400 mW cm-2 ), outstanding electromagnetic interference shielding effectiveness (37 dB), and excellent antibacterial performances (>90% anti-bacterial rate toward Escherichia coli, Bacillus subtilis, and Staphylococcus aureus). This work offers an efficient avenue to fabricate multifunctional wearable thermal therapy devices for mobile healthcare and personal thermal management.

Aqueous zinc-ion batteries (ZIBs) are currently receiving widespread attention due to their merits of environmental-friendly properties, high safety, and low cost. However, the absence of stable zinc metal anodes severely restricts their potential applications. In this work, we demonstrate a simple oxygen plasma treatment method to modify the surface state of carbon cloth to construct an ideal substrate for zinc deposition to solve the dendrite growth problem of zinc anodes. The plasma treated carbon cloth (PTCC) electrode has lower nucleation overpotential and uniformly distributed C=O zincophilic nucleation sites, facilitating the uniform nucleation and subsequent homogeneous deposition of zinc. Benefiting from the superior properties of PTCC substrate, the enhanced zinc anodes demonstrate low voltage hysteresis (about 25 mV) and stable zinc plating/stripping behaviors (over 530 h lifespan) at 0.5 mA cm−2 with 15% depth of discharge (DOD). Besides, an extended cycling lifespan of 480 h can also be achieved at very high DOD of 60%. The potential application of the enhanced zinc anode is also confirmed in Zn|V10O24·12H2O full cell. The cells with Zn@PTCC electrode demonstrate remarkable rate capability and excellent cycling stability (95.0% capacity retention after 500 cycles).

Lithium-sulfur (Li-S) battery owing to high energy density and theoretical capacity is anticipated as a high-performance rechargeable power source for flexible electronic devices and electric vehicles. However, the rapid capacity fade, low Coulombic efficiency, and significant self-discharge capacity loss due to the polysulfides shuttling are the major constraints of its real-world applications. To conquer these challenges, despite the physical encapsulation of polysulfides, chemical interactions between shuttle effect-suppressive sulfur host materials and soluble lithium polysulfides have recently been emphasized. Herein, a novel approach to synthesize the high entropic stabilized oxide (HEO) at low temperature is developed from the self-sacrificing template of metal-organic frameworks (MOFs) to chemically anchor the lithium polysulfides. As-synthesized HEO850 at 850 ºC (transition temperature) exhibited a single-phase rocksalt crystalline structure with homogenous dispersion of Ni, Mg, Cu, Co, and Zn and reversible entropic phase stabilization in the certain temperature range (750-850 ºC). When employed as a chemical anchor to lithium polysulfides (LIPSs) and compared the electrochemical performance of Li-S cells with medium configurational entropic oxide (MEOs) (HEOs-one metal cation), low entropy oxide (LEOs) (HEOs-three metal cations), and routine sulfur ketjen black (S/KB) cells, it revealed a competitive reversible capacity, excellent cycling stability and a low capacity decay rate by immobilizing the LIPSs and facilitating the redox reaction in the cathode. The cells with HEO850/KB/S cathode delivered a higher initial specific discharge capacity of 1244.1 mAh g-1 than those of MEO850/S/KB (979.625 mAh g-1), LEO850/S/KB (908 mAh g-1), and S/KB (966 mAh g-1). After 800 cycles of continuous charging and discharging at 0.5 C, the capacity of 784.1 mAh g-1 with outstanding Coulombic efficiency of 99.66 % is still retained demonstrating excellent cycling stability with a negligible capacity fade rate of 0.04% per cycle. This outstanding performance could be attributed to the synergistic contribution and exposure of numerous active sites of randomly dispersed elements in the HEO850. This study not only highlights the extraordinary electrochemical performance of Li-S battery with efficient immobilization of LIPSs but also provide a novel strategy for the synthesis of HEOs at lower calcination temperature for various energy conversion and storage applications. After getting confidence with these prilimary results, Ti-based HEOs owing to both high ionic and electric conductivities will be investigated at coin and pouch cell level as future research direction.

Rechargeable aqueous zinc-ion batteries have attracted extensive interest because of low cost and high safety.However,the relationship between structure change of cathode and the zinc ion storage mechanism is still complex and challenging.Herein,open-structured ferric vanadate(Fe 2 V 4 O 13 ) has been developed as cathode material for aqueous zinc-ion batteries.Intriguingly,two zinc ion storage mechanism can be observed simultaneously for the Fe 2 V 4 O 13 electrode,i.e.,classical intercalation/deintercalation storage mechanism in the tunnel structure of Fe 2 V 4 O 13 ,and reversible phase transformation from ferric vanadate to zinc vanadate,which is verified by combined studies using various in-situ and ex-situ techniques.As a result,the Fe 2 V 4 O 13 cathode delivers a high discharge capacity of 380 mAh/g at 0.2 A/g,and stable cyclic performance up to 1000 cycles at 10 A/g in the operating window of 0.2-1.6 V with 2 mol/L Zn（CF 3 SO 3 ） 2 aqueous solution.Moreover,the assembled Fe 2 V 4 O 13 //Zn flexible quasi-solid-state battery also exhibits a relatively high mechanical strength and good cycling stability.The findings reveal a new perspective of zinc ion storage mechanism for Fe 2 V 4 O 13 ,which may also be applicable to other vanadate cathodes,providing a new direction for the investigation and design of zinc-ion batteries.

Aqueous rechargeable zinc-ion batteries have attracted much attention due to high safety, fast charge/discharge rate, low cost and direct utilization of zinc metal anodes. However, zinc anodes suffer from fundamental issues and elusiveness of critical information such as its nucleation and plating/stripping behaviors. Herein, we explore nucleation pattern of zinc on various metal substrates (Cu, Ag, Ti or Sn) and discover a substrate-dependent plating/stripping behavior. With use of binary diagrams (Ag|Cu, Ti|Cu and Cu|Sn), we found that zinc has a selective deposition on Cu substrates with no nucleation barriers. Theoretical calculation also indicates a relatively low bonding energy between Zn and Cu. Besides, it is also found that Sn inhibits growth of by-product of basic zinc sulfates. Thereafter, we report a layer-by-layer construction of zinc metal (Sn/Cu/Zn) anode for long-life zinc-ion batteries. Our work paves a way to understand plating/stripping behavior of metal anodes and to design layer-by-layer metal anodes for metal batteries.

The battery chemistry of zinc-ion batteries (ZIBs) typically involves the insertion/extraction of Zn2+ and H+ into/from cathode materials, for example, manganese oxides, vanadium oxides, Prussian blue analogs, etc. Nonetheless, Zn2+ and H+ insertion into those cathodes are generally accompanied by lattice distortion, phase transition, and volume expansion, resulting in rapid degradation of the battery. Here, MoS2 with a high purity 1T phase (TH-MoS2) is reported as new ZIB cathode, which has a high capacity, an extended cycle life, and, an excellent rate capacity. The ex-situ characterizations elucidate that TH-MoS2 achieves highly reversible Zn2+ storage with negligible phase transition, volume change, and lattice distortion upon cycle. Based on kinetic analysis and calculations results, the reaction mechanism of TH-MoS2 electrode is dominated by pseudocapacitive behavior, which ensure the prominent cycle and rate performance.

Rechargeable aqueous zinc ion battery (RAZIB) is a promising energy storage system due to its high safety, and high capacity. Among them, manganese oxides with low cost and low toxicity have drawn much attention. However, the under-debate proton reaction mechanism and unsatisfactory electrochemical performance limit their applications. Nanorod β-MnO2 synthesized by hydrothermal method is used to investigate the reaction mechanism. As cathode materials for RAZIB, the Zn//β-MnO2 delivers 355 mAh g−1 (based on cathode mass) at 0.1 A g−1, and retain 110 mAh g−1 after 1000 cycles at 0.2 A g−1. Different from conventional zinc ion insertion/extraction mechanism, the proton conversion and Mn ion dissolution/deposition mechanism of β-MnO2 is proposed by analyzing the evolution of phase, structure, morphology, and element of β-MnO2 electrode, the pH change of electrolyte and the determination of intermediate phase MnOOH. Zinc ion, as a kind of Lewis acid, also provides protons through the formation of ZHS in the proton reaction process. This study of reaction mechanism provides a new perspective for the development of Zn//MnO2 battery chemistry.

Abstract Aqueous Zn-ion hybrid supercapacitors (ZHSs) are increasingly being studied as a novel electrochemical energy storage system with prominent electrochemical performance, high safety and low cost. Herein, high-energy and anti-self-discharge ZHSs are realized based on the fibrous carbon cathodes with hierarchically porous surface and O/N heteroatom functional groups. Hierarchically porous surface of the fabricated free-standing fibrous carbon cathodes not only provides abundant active sites for divalent ion storage, but also optimizes ion transport kinetics. Consequently, the cathodes show a high gravimetric capacity of 156 mAh g−1, superior rate capability (79 mAh g−1 with a very short charge/discharge time of 14 s) and exceptional cycling stability. Meanwhile, hierarchical pore structure and suitable surface functional groups of the cathodes endow ZHSs with a high energy density of 127 Wh kg−1, a high power density of 15.3 kW kg−1 and good anti-self-discharge performance. Mechanism investigation reveals that ZHS electrochemistry involves cation adsorption/desorption and Zn4SO4(OH)6·5H2O formation/dissolution at low voltage and anion adsorption/desorption at high voltage on carbon cathodes. The roles of these reactions in energy storage of ZHSs are elucidated. This work not only paves a way for high-performance cathode materials of ZHSs, but also provides a deeper understanding of ZHS electrochemistry.

Rechargeable aqueous zinc-ion batteries (ZIBs) have become a research hotspot in recent years, due to their huge potential for high-energy, fast-rate, safe and low-cost energy storage. To realize good electrochemical properties of ZIBs, cathode materials with prominent Zn2+ storage capability are highly needed. Herein, we report a promising ZIB cathode material based on electrochemically induced transformation of vanadium oxides. Specifically, K2V6O16.1.5H2O nanofibers were synthesized through a simple stirring method at near room temperature and then used as cathode materials for ZIBs in different electrolytes. The cathode presented superior Zn2+ storage capability in Zn(OTf)2 aqueous electrolyte, including high capacity of 321 mAh/g, fast charge/discharge ability (96 mAh/g delivered in 35 s), high energy density of 235 Wh/kg and good cycling performance. Mechanism analysis evidenced that in Zn(OTf)(2) electrolyte, Zn2+ intercalation in the first discharge process promoted K(2)V(6)O16.1.5H(2)O nanofibers to transform into Zn-3+xV(2)O(7)(OH)2.2H(2)O nanoflakes, and the latter served as the Zn2+-storage host in subsequent charge/discharge processes. Benefiting from open-framework crystal structure and sufficiently exposed surface, the Zn-3+xV(2)O(7)(OH)2.2H(2)O nanoflakes exhibited high Zn2+ diffusion coefficient, smaller charge-transfer resistance and good reversibility of Zn2+ intercalation/de-intercalation, thus leading to superior electrochemical performance. While in ZnSO4 aqueous electrolyte, the cathode material cannot sufficiently transform into Zn(3+)xV(2)O(7)(OH)2.2H(2)O, thereby corresponding to inferior electrochemical behaviors. Underlying mechanism and influencing factors of such a transformation phenomenon was also explored. This work not only reports a high-performance ZIB cathode material based on electrochemically induced transformation of vanadium oxides, but also provides new insights into Zn2+-storage electrochemistry. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.