Hydrogenated V2O5 with fast Zn-ion migration kinetics as high-performance cathode material for aqueous zinc-ion batteries

Abstract

The scarce inventory of cathode materials with mild interaction between Zn2+ and cathode lattice is the main obstacle to the development for aqueous rechargeable Zinc-ion batteries. In this paper, based on the first-principles calculations, we show that the insertion of protons in V2O5 effectively reduces the electrostatic interaction and the Zn-ion diffusion energy barrier in V2O5 substantially decreases after hydrogenation. Hence, the hydrogenated V2O5 (HV2O5) nanospheres are first proposed as a high capacity cathode for aqueous rechargeable Zinc-ion batteries by microwave-assisted chemical precipitation synthesis. It is demonstrated to exhibit high peak capacities of 602 mAh g−1 at 0.1 A g−1, high rate capacity as well an excellent cycle lifespan with a capacity retention of 86% after 5000 cycles at 10 A g−1. The mechanism of ions-diffusion in different charge and discharge states is also studied, and it proves dual-ion energy storage mechanism that HV2O5 can attract Zn ions and H ions at discharging.