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

High-performance cathodes are essential for all kinds of rechargeable batteries, and vanadium pentoxide (V2O5) has wide applications as a cathode in various batteries because of its high theoretical capacity, abundant reserves, and high safety performances. However, the irreversible phase transitions and sluggish ion diffusion limit its advancements. Herein, morphology-tunable micron-sized nanoporous V2O5 arrays are synthesized from V2CTx MXene by a one-step annealing process. The component and structure of the V2CTx MXene are simply controlled by regulating the reaction time. The effects of annealing conditions on crystallinity, microstructure, and electrochemical performance of V2O5 are further probed. The rationally designed V2O5 possesses special porous architecture, 2D structure, and pseudocapacitive effect, which ensures high ion accessibility, excellent structure stability, and fast charge transport. As a consequence, the optimal V2O5 cathode for gel zinc-ion batteries exhibits high 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 (279 mA h g–1 at 2000 mA g–1 over 3500 cycles). The zinc storage enhancing mechanism is assessed by quantitative kinetics analysis. Furthermore, the V2O5 cathode also delivers an improved potassium storage performance. This work may provide a universal avenue to fabricate high-performance electrodes from MXene-based materials for next generation battery systems.