Metal-organic-framework-derived cobalt-vanadium oxides with tunable compositions for high-performance aqueous zinc-ion batteries

As one of next-generation energy storage devices, aqueous zinc-ion batteries (ZIBs) have received increasing attention owing to the merits of low cost, high safety and eco-friendliness. However, challenges still exist in searching for high-performance cathode materials with microstructural engineering and morphology design. Herein, a dissolution-regrowth and conversion strategy are developed by using metal-organic framework template, which facilitate in situ formation of CoVOx oxide with porous one-dimensional channels and unique nanostructures. Owing to the unique structure, Zn2+ ions which are inserted directly into the host CoVOx-2 nanoplate to allow the high diffusion and low interfacial resistance. Consequently, the CoVOx-2 nanoplate cathode delivers a high reversible capacity of 288 mAh/g at 0.05 A/g and long cycle life at low current density of 1 A/g (94 % of the highest capacity is maintained at 1 A/g after 1000 cycles). Moreover, the reversible storage mechanism is confirmed by a series of ex-situ physical characterization and electrochemical performance investigation. These findings provide a new insight into high-performance MOF-derived unique structure designs for rechargeable battery electrodes.