Vanadium Pentoxide Nanosheets in-Situ Spaced with Acetylene Black as Cathodes for High-Performance Zinc-Ion Batteries.

The 2D materials of ultrathin nanosheets possess plentiful active sites, effectively enhancing the electrochemical kinetics of various electrode materials. However, 2D materials usually suffer from the aggregation issue due to the strong van der Waals force of the individual nanosheets, leading to irreversible stacking and decreasing capacity. In this work, we develop a universal method to in-situ space the nanosheet cathodes for the electrodes of ZIBs. As a proof of concept, the V2O5 nanosheets with in-situ AB spacer were obtained, which were used as the cathode of aqueous ZIBs. Owing to plentiful active sites usable for electrolyte/electrode interfaces of the spaced V2O5, the ion diffusion kinetics of the electrodes would be enhanced. In contrast with the stacked V2O5, the spaced V2O5 delivers an exceptional specific capacity (452 mAh g-1), superior rate capability, and stable cycle life (the capacity retention of 92% after 5000 cycles). Moreover, the resultant ZIBs assembled with spaced V2O5 show an impressive energy/power density (158 Wh kg-1 at 19.3 kW kg-1). These superior electrochemical properties make the method of in-situ adding AB spacer hold promising potential to obtain advanced nanosheet electrodes for energy storage systems.