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An unprecedented SIB materials based C@NCS@V 4 C 3 T x with good cooperative interfaces was reported. Benefitting from the synergetic effects derived from the built cooperative interfaces, the C@NCS@V 4 C 3 T x hybrid exhibited an ultrahigh reversible specific capacity and the corresponding good reversible capacity, both higher than those of same kind batteries. Assembled full-cell delivers outstanding electrochemical properties that can be useful as a portable integrated unit for self-powered systems. [Display omitted] • Fewer layers of V 4 C 3 T x nanosheet sites are available for sodium storage. • A high-efficiency anode was designed by a pseudo-isotope synthesis strategy. • The full-cell shows high-rate and superior cycling performance. Materials used for conventional conversion-type anodes usually suffer from poor charge transfer and short lifespan, thereby limiting their utility in sodium-ion batteries (SIBs). To prevent these issues, the development of new anode materials is imperative. Herein, we used a synergistic modification strategy based on pseudo-isotopic substitution and 2D conductive skeleton support, to successfully prepare an unprecedented (Co 0.5 Ni 0.5)S 2 @V 4 C 3 T x with carbon layer coating (C@NCS@V 4 C 3 T x) anode materials for SIBs. We noted that the C@NCS@V 4 C 3 T x hybrid exhibited an ultrahigh reversible specific capacity of 705.6 mAh g−1 at 0.1 Ag−1, and the corresponding reversible capacity that is 100-times higher (10 A g−1) at a specific heat capacity of 347.6 mAh g−1, both higher than those of same kind batteries. Furthermore, the as-prepared hybrid also shows satisfactory long-term cycling stability, resulting from 2D skeleton V 4 C 3 T x MXene with high conductivity and robustness. Through in-situ characterization techniques and density functional theory calculations, the sodium ions storage mechanism was well-investigated, specifically, the synergy effect between the high capacity of bimetallic TMS and metallic conductivity and excellent stability of V 4 C 3 T x MXene plays an important role in high-performance achievement. Thus, assembled C@NCS@V 4 C 3 T x //Na 3 V 2 (PO 4) 3 full-cell delivers outstanding electrochemical properties that can be useful as a portable integrated unit for self-powered systems. [ABSTRACT FROM AUTHOR]

Benefiting from the structure and electronic engineering, the self-supported N doped NiSe 2 hierarchically nanoflake arrays grown on flexible carbon cloth present superior performance with high stability and robust flexibility for solid-state zinc-air batteries. • The self-supported cathode electrode can satisfy the flexibility for solid-state zinc-air batteries. • Nitrogen doping can optimize the electronic structure and absorption feature of NiSe 2. • The open and porous structure provides more active sites and facilitates the mass transfer process. • N-NiSe 2 /CC exhibits outstanding performance for oxygen evolution/reduction reaction and zinc-air batteries. Rational design of efficient bifunctional air cathodes towards oxygen evolution/reduction reaction is of central importance for energy-efficient metal-air batteries, but remains an ongoing challenge. Here, N element doped NiSe 2 nanosheets in-situ grown on the carbon cloth were prepared via facial hydrothermal synthesis of nickel hydroxide followed by selenization and nitrogen doping treatment. Such self-supported N-doped NiSe 2 nanoarrays (N-NiSe 2 /CC) exhibits superior bifunctional catalytic activity and high durability compared with the pristine NiSe 2 /CC, which are ascribed to the unique structure after nitrogen doping. Nitrogen doping can provide more electrocatalytical active sites and improve the electronic transport for fast reaction kinetics, which is preferably corroborated with density functional theory calculations and X-ray absorption spectroscopy. As a proof of concept, the solid-state zinc-air batteries assembled by the N-NiSe 2 /CC directly as the air cathode present a low overpotential of 0.75 V, remarkable cyclic stability of 30 h with 90 circles, and robust flexibility. Therefore, the N-NiSe 2 /CC system proves to be a highly active and reliable electrode for the developing of metal-air batteries, opening up a promising opportunity for high-performance portable electronics. [ABSTRACT FROM AUTHOR]