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Solid‐state energy storage devices (SSESDs) are believed to significantly improve safety, long‐term electrochemical/thermal stability, and energy/power density as well as reduce packaging demands, showing the huge application potential in large‐scale energy storage. Nevertheless, some key issues like low ionic conductivities, poor interface contact, and dendrites growth limit the practical application of SSESDs. In recent years, MXenes for SSESDs have received reassuring advances on account of unique parameters. Nevertheless, overall reviews about the subject are seldom. In this review, current advances of MXenes and their derivatives in solid‐state Li–metal, Li‐ion, Li–I/S, Na‐ion, Zn–air, Zn–metal batteries, and supercapacitors in cathode/anode optimization, interface medication, and electrolyte fillers, etc., are comprehensively reviewed. First of all, essential principles of MXenes are shown, such as precursors, etching/delamination strategies, as well as superior properties for energy storage systems. Meanwhile, the classification and evaluation parameters of solid‐state electrolytes are summarized. Subsequently, the application, modification mechanism, and design strategy of MXenes for boosting electrochemical behaviors of SSESDs are systematically reviewed and discussed. At last, perspectives and challenges about the future construction strategies of MXenes for SSESDs are recommended. This review shall assist scientists design and build advanced SSESDs with superior energy density along with safety. [ABSTRACT FROM AUTHOR]

Bio‐organisms with various architectures and versatile physiological functions provide a substantial bibliography for electrode design. To elucidate how bio‐organisms and bio‐schemes take effect in advanced electrode materials, this review sorts bio‐assisted construction into two categories, namely, biotemplating synthesis and biomimetic artificial fabrication. The former section summarizes unique characteristics of different biotemplates for electrode preparation, including "bottom‐up" structural designability of biomolecules, metabolism involving, and genetic alterable properties of biological cells, as well as, the structural regularity and integrity of bio‐tissues, with the aim to provide guidelines for manipulating bioarchitectures and endow biotemplating synthesis of electrodes with more designability. The later describes recent efforts in using bio‐prototypes to enhance the essential properties associated with advanced electrodes, including mechanical properties, wettability, mass transport, electron/charge transfer, and catalytic activity, with intensive concerns on the function principles of biomimetic designs in electrochemical systems. Then, advances in applications of bioderived and biomimetic electrode materials are summarized emphasizing how bio‐structures/components and bionic designs help to enhance the charging/discharging and electrocatalytic performance in specific electrochemical energy storage and conversion systems. Finally, future trends with prospects and challenges for developing new bioderived/biomimetic electrode materials, as well as, related conceptual innovation on bionics, are discussed in the last section. [ABSTRACT FROM AUTHOR]

Cost-effectively, eco-friendly rechargeable aqueous zinc-ion batteries (AZIBs) have reserved widespread concerns and become outstanding candidate in energy storage systems. However, the progress pace of AZIBs suffers from limitation of suitable and affordable cathode materials. Herein, a double-effect strategy is realized in a one-step hydrothermal treatment to prepare V2O5 nanoribbons with intercalation of Ce and introduction of abundant oxygen defects (Od-Ce@V2O5) to enhance electrochemical performance synergistically. Coupled with the theoretical calculation results, the introduction of Ce ions intercalation and oxygen vacancies in V2O5 structure enhances the electrical conductivity, reduces the adsorption energy of zinc ions, enlarges the interlayer distance, renders the structure more stable, and facilitates rapid diffusion kinetics. As expected, the desirable cathode delivers the reversible capacity of 444 mAh·g−1 at 0.5 A·g−1 and shows excellent Coulombic efficiency, as well as an extraordinary energy density of 304.9 Wh·kg−1. The strategy proposed here may aid in the further development of cathode materials with stable performance for AZIBs. [ABSTRACT FROM AUTHOR]

Aqueous zinc–ion batteries (ZIBs) have been promptly developed as a competitive and promising system for future large‐scale energy storage. In recent years, vanadium (V)‐based compounds, with diversity of valences and high electrochemical‐activity, have been widely studied as cathodes for aqueous ZIBs because of their rich reserves and high theoretical capacity. However, the stubborn issues including low conductivity and sluggish kinetics, plague their smooth application in aqueous ZIBs. Among various countermeasures, defect engineering is believed as an effective method to alleviate the above limitations. This review highlights the challenges of different V‐based cathode materials (e.g., vanadium oxides and vanadates) and summarizes the advances in defect engineering strategies including types and effects of the defects, designed strategies, and characterization techniques for high‐energy ZIBs. Finally, several sound prospects in this fervent field are also rationally proposed for fundamental research and practical application. [ABSTRACT FROM AUTHOR]

Anode‐free zinc batteries (AFZBs) are proposed as promising energy storage systems due to their high energy density, inherent safety, low cost, and simplified fabrication process. However, rapid capacity fading caused by the side reactions between the in situ formed zinc metal anode and electrolyte hinders their practical applications. To address these issues, aqueous AFZBs enabled by electrolyte engineering to form a stable interphase are designed. By introducing a multifunctional zinc fluoride (ZnF2) additive into the electrolyte, a stable F‐rich interfacial layer is formed. This interfacial layer can not only regulate the growth orientation of zinc crystals, but also serve as an inert protection layer against side reactions such as H2 generation. Based on these synergy effects, zinc deposition/dissolution with high reversibility (Coulombic efficiency > 99.87%) and stable cycling performance up to 600 h of are achieved in the electrolyte optimized by ZnF2. With this electrolyte, the cycling life of AFZBs is significantly improved. The work may initiate the research of AFZBs and be useful for the design of high energy, high safety, and low‐cost power sources. [ABSTRACT FROM AUTHOR]

Silicon (Si) and lithium metal are the most favorable anodes for high‐energy‐density lithium‐based batteries. However, large volume expansion and low electrical conductivity restrict commercialization of Si anodes, while dendrite formation prohibits the applications of lithium‐metal anodes. Here, uniform nanoporous Si@carbon (NPSi@C) from commercial alloy and CO2 is fabricated and tested as a stable anode for lithium‐ion batteries (LIBs). The porosity of Si as well as graphitization degree and thickness of the carbon layer can be controlled by adjusting reaction conditions. The rationally designed porosity and carbon layer of NPSi@C can improve electronic conductivity and buffer volume change of Si without destroying the carbon layer or disrupting the solid electrolyte interface layer. The optimized NPSi@C anode shows a stable cyclability with 0.00685% capacity decay per cycle at 5 A g−1 over 2000 cycles for LIBs. The energy storage mechanism is explored by quantitative kinetics analysis and proven to be a capacitance‐battery dual model. Moreover, a novel 2D/3D structure is designed by combining MXene and NPSi@C. As lithiophilic nucleation seeds, NPSi@C can induce uniform Li deposition with buffered volume expansion, which is proven by exploring Li‐metal deposition morphology on Cu foil and MXene@NPSi@C. The practical potential application of NPSi@C and MXene@NPSi@C is evaluated by full cell tests with a Li(Ni0.8Co0.1Mn0.1)O2 cathode. [ABSTRACT FROM AUTHOR]

[Display omitted] The practical application of lithium–sulfur (Li–S) batteries is inhibited by the shuttle effect of lithium polysulfides (LiPSs) and slow polysulfide redox kinetics on the S cathode as well as the uncontrollable growth of dendrites on the Li metal anode. Therefore, both cathode and anode sides must be considered when modifying Li−S batteries. Herein, two-dimensional (2D) ultrathin CoSe 2 nanobelts are in situ grown on 2D N-doped MXene nanosheets (CoSe 2 @N-MXene) via one-step solvothermal process for the first time. Owing to its unique 2D/2D structure, CoSe 2 @N-MXene can be processed to crumpled nanosheets by freeze-drying and flexible and freestanding films by vacuum filtration. These crumpled CoSe 2 @N-MXene nanosheets with abundant active sites and inner spaces can act as S hosts to accelerate polysulfide redox kinetics and suppress the shuttle effect of LiPSs owing to their strong adsorption ability and catalytic conversion effect with LiPSs. Meanwhile, the CoSe 2 @N-MXene film (CoSe 2 @NMF) can act as a current collector to promote uniform Li deposition because it contains lithiophilic CoSe 2 and N sites. Under the systematic effect of CoSe 2 @N-MXene on S cathode and Li metal anode, the electrochemical and safety performance of Li–S batteries are improved. CoSe 2 @NMF also shows excellent storage performances in flexible energy storage devices. [ABSTRACT FROM AUTHOR]

A systematic overview of dealloying technique in electrochemical energy storage is presented. [Display omitted] • A review specialized dealloying technique in energy storage. • Characters, fundaments, and advantages of dealloying technique. • Dealloying techniques, including chemical, electrochemical, and vapor dealloying. • 0D, 1D, 2D, and 3D materials fabricated by dealloying technique. • Applications, challenges and future development of dealloying technique in energy storage. Nanomaterials have promising applications in catalysis, filtration, hydrogen storage, sensors, automobile exhaust treatment, and energy storage and conversion, etc. However, scalable and economic fabrication of nanomaterials remains a challenge. In the past century, the world has witnessed successful industrialization of nanoporous Raney nickel in thousands of tons per year by dealloying method. With the advantages of low cost, scalable fabrication and controllable structure, dealloying technique has attracted more attention and gained wider applied in numerous areas. This review attempts to summarize the recent progress in development of dealloying technique, with special emphasis on synthetic materials (0D, 1D, 2D, 3D) and advanced applications, including lithium-ion batteries, lithium-oxygen batteries, lithium-sulfur batteries, lithium-metal batteries, zinc-metal batteries, sodium-ion batteries, magnesium-ion batteries, potassium-ion batteries, aluminum-ion batteries, aluminum-carbon dioxide batteries, and supercapacitors, etc. The advantages, theoretical research, and influence factors of dealloying technique are also analyzed. Besides, key scientific issues and prospective directions of dealloying technique are also discussed. We believe this review may attract more researchers in relevant fields and offer some guide for the future development of dealloying technique. [ABSTRACT FROM AUTHOR]

[Display omitted] Due to their unique properties, a lot of two-dimensional (2D) materials have been predicted and produced in the past decades. Furthermore, 2D materials have exhibited great application prospects in various frontier fields. Silicene as a novel 2D material has become the research interest of scientists and engineers in recent years. In this review, we firstly review the conception, structure, and properties of silicene. Then, we summarize the advanced fabrication methods of 2D silicene/silicon as direct fabrication techniques, dealloying techniques, metallic reduction techniques, and topochemical techniques, and discuss the merits and demerits of every fabrication method. In addition, the investigations about silicene derivatives are also summarized and discussed. Subsequently, the utilizations of 2D silicene/silicon and its derivatives in energy storage devices, catalysts, biomedicine, sensors, and electronic devices are reviewed. Finally, further development of preparation methods and application advances of 2D silicene/silicon and its derivatives are prospected. This review shall assist scientists in the fabrication and application of 2D silicene/silicon and its derivatives on above frontier applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Structural editing strategy for low-dimensional Mxenes with manipulable structural chemistry were proposed. • Their structural chemistry were modulating by co-anchored dual-ultrasmall Sb and Sb 6 O 13 nanodots. • These structural editing evolution processes were evaluated by experimental measurements and theoretical calculations. • Their advanced architectures modulating bidirectional kinetics of polysulfides redox and lithium deposition. Exfoliation and modulation of intercalated layered transition metal carbides and/or nitrides (MAX) into their derivatives (MXenes) featured with manipulable structural chemistry by remain enormous challenges toward practical applications. Herein, an extraordinary low-dimensional MXenes modulated by dual-ultrasmall Sb and Sb 6 O 13 nanodots via in situ structural editing protocol using Lewis-basic fluorides in organic molten salts. Their original internal non-van der Waals bonds and physicochemical natures are simultaneously mediated by manipulating fluorine anions and antimony cations as chemical scissors generating into zero- and one-dimensional MXenes (MFNCTS-Z, MFNCTS-O) encapsulated by hierarchical porous N-doped carbon. Experimental and theoretical results manifest MFNCTSs as alternative dual-functional hosts toward both sulfur (S) cathode and lithium (Li) anode modulating bidirectional kinetics originated from their synergistic effect of physical confinement and chemical anchor effect accelerating polysulfides redox chemistry, and homogeneous lithium deposition. As a result, the assembled lithium-sulfur full batteries offer impressive electrochemical performances. This work paves a new avenue for developing low-dimensional MXenes by controllable structural editing strategy toward practical energy conversion and storage fields. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2D TiO 2 is synthesized from Ti 3 C 2 T x MXene via one-step hydrothermal reaction. • A robust and flexible polymer/ TiO 2 hybrid gel electrolyte is designed. • 2D TiO 2 can improve the mechanical properties and ionic conductivity of gel. • The hybrid gel electrolyte can regulate Zn depositing/stripping. • Full Zn||PVA-Zn(CF 3 SO 3) 2 -TiO 2 ||V 2 O 5 cell exhibits enhanced performance. Gel electrolytes are key components for flexible energy storage devices. However, disadvantages such as poor ionic conductivity and mechanical behavior limit the practical applications of gel electrolytes. Herein, two-dimensional TiO 2 nanosheets are fabricated from Ti 3 C 2 T x MXene by a one-step hydrothermal reaction. The structure and component of Ti 3 C 2 T x MXene can be easily controlled by modulating the synthesis conditions. Influences of TiO 2 nanosheets content in PVA-based gel electrolyte are explored, which brings higher ionic conductivity and better mechanical properties with suitable additive amount. As a consequence, with the hybrid gel electrolyte, highly stable Zn plating/stripping is achieved (over 3000 h at 0.5 mA cm−2). Full Zn||PVA-Zn(CF 3 SO 3) 2 -TiO 2 ||V 2 O 5 cell shows high capacity (216 mAh g−1 after 115 cycles) and excellent cycling performance. This work provides an alternative route to develop high performance hybrid gel electrolyte for flexible energy storage devices such as Li/Na/K/Zn and supercapacitors. [ABSTRACT FROM AUTHOR]