Mn2+ as the "spearhead" preventing the trap of Zn2+ in layered Mn2+ inserted hydrated vanadium pentoxide enables high rate capacity.

Abstract Vanadium oxides attract much attention and are concerned as one of the most promising cathodes for aqueous zinc-ion batteries (AZIBs) owing to the layered structures. However, their intensive development is limited by the fragile structures and laggard ion-transferring. Herein, Mn2+ inserted hydrated vanadium pentoxide nanobelts/reduced graphene oxide (MnxV2O5·nH2O/rGO, abbreviated as MnVOH/rGO) was prepared by a simple one-pot hydrothermal process, delivering excellent electrochemical properties for AZIBs. The Zn//MnVOH/rGO cell operates well even at changing current densities over 45 cycles, behaving 361 mAh·g−1 at 0.1 A·g−1, 323 mAh·g−1 as the current density gradually increasing to 2 A·g−1 and 350 mAh·g−1 when gradually back to 0.1 A·g−1 (∼97% of initial capacity). Such a superb cycling and rate performance is ascribed to the unique stable structure with the compact electrostatic attraction between Mn2+ and V2O5·nH2O (VOH) laminate. On the one hand, Mn2+ generates electrostatic network with [VO6] polyhedrons and suppresses the following electrostatic trap for the moving Zn2+. On the other hand, rGO improves the conductivity, endowing the high capacity and energy density. The performance of the MnVOH/rGO cathode exceeds most of vanadium-based cathodes applying in AZIBs and paves the way to the ideal energy storage system.