2D Amorphous V2O5/Graphene Heterostructures for High-Safety Aqueous Zn-Ion Batteries with Unprecedented Capacity and Ultrahigh Rate Capability

Rechargeable aqueous zinc-ion batteries (ZIBs) are appealing due to their high safety, zinc abundance, and low cost. However, developing suitable cathode materials remains a great challenge. Herein, a novel 2D heterostructure of ultrathin amorphous vanadium pentoxide uniformly grown on graphene (A-V2O5/G) with a very short ion diffusion pathway, abundant active sites, high electrical conductivity, and exceptional structural stability, is demonstrated for highly reversible aqueous ZIBs (A-V2O5/G-ZIBs), coupling with unprecedented high capacity, rate capability, long-term cyclability, and excellent safety. As a result, 2D A-V2O5/G heterostructures for stacked ZIBs at 0.1 A g(-1) display an ultrahigh capacity of 489 mAh g(-1), outperforming all reported ZIBs, with an admirable rate capability of 123 mAh g(-1) even at 70 A g(-1). Furthermore, the new-concept prototype planar miniaturized zinc-ion microbatteries (A-V2O5/G-ZIMBs), demonstrate a high volumetric capacity of 20 mAh cm(-3) at 1 mA cm(-2), long cyclability; holding high capacity retention of 80% after 3500 cycles, and in-series integration, demonstrative of great potential for highly-safe microsized power sources. Therefore, the exploration of such 2D heterostructure materials with strong synergy is a reliable strategy for developing safe and high-performance energy storage devices.