Micron-Sized Nanoporous Vanadium Pentoxide Arrays\nfor High-Performance Gel Zinc-Ion Batteries and Potassium Batteries

Abstract

High-performance\ncathodes are essential for all kinds of rechargeable\nbatteries, and vanadium pentoxide (V₂O₅) has\nwide applications as a cathode in various batteries because of its\nhigh theoretical capacity, abundant reserves, and high safety performances.\nHowever, the irreversible phase transitions and sluggish ion diffusion\nlimit its advancements. Herein, morphology-tunable micron-sized nanoporous\nV₂O₅ arrays are synthesized from V₂CT_<i>x</i> MXene by a one-step annealing process.\nThe component and structure of the V₂CT_<i>x</i> MXene are simply controlled by regulating the reaction time.\nThe effects of annealing conditions on crystallinity, microstructure,\nand electrochemical performance of V₂O₅ are\nfurther probed. The rationally designed V₂O₅ possesses special porous architecture, 2D structure, and pseudocapacitive\neffect, which ensures high ion accessibility, excellent structure\nstability, and fast charge transport. As a consequence, the optimal\nV₂O₅ cathode for gel zinc-ion batteries exhibits\nhigh capacity (358.7 mA h g^–1 at 200 mA g^–1 after 400 cycles), superior rate performance (250.4 mA h g^–1 at 8000 mA g^–1), and stable long-term cyclability\n(279 mA h g^–1 at 2000 mA g^–1 over\n3500 cycles). The zinc storage enhancing mechanism is assessed by\nquantitative kinetics analysis. Furthermore, the V₂O₅ cathode also delivers an improved potassium storage performance.\nThis work may provide a universal avenue to fabricate high-performance\nelectrodes from MXene-based materials for next generation battery\nsystems.