Ultralarge layer spacing and superior structural stability of V₂O₅ as high-performance cathode for aqueous zinc-ion battery

Aqueous zinc (Zn)-ion batteries (AZIBs) present safe and environmentally friendly features thereby emerging as an attractive energy storage device. The V₂O₅-based cathodes are promising because of their high theoretical capacity and energy density. However, insufficient interlayer distance, easy dissolution and structural collapse due to irreversible crystalline phase transition limit the development of V₂O₅ cathodes in AZIBs. Herein, doubly modified V₂O₅-based cathode which was in-situ intercalated by polyaniline (PANI) and composited with MXene (Ti₃C₂T_x) (denoted PVM) were synthesized by one-step method for the first time. The in situ intercalation of PANI provides a channel for the rapid diffusion of Zn²⁺ and the heterogeneous structures effectively promote charge transfer and enable structural integrity of cathode during cycling. Meanwhile, the conductivity of PVM electrode is greatly improved. Specifically, the PVM electrode shows a superior rate performance of 82 mAh·g⁻¹ after 2000 cycles at 10 A·g⁻¹. And it shows high pseudocapacitance behavior (80.23% capacitor contribution ratio at 0.1 mV·s⁻¹). A novel method of intercalation composite modification for the cathode is proposed, which provides fundamental guidance for the development of high-performance cathodes for AZIBs.