V2O5/NaV6O15 nanocomposites synthesized by molten salt method as a high-performances cathode material for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) is a potential energy storage system due to its advantages of low cost, good safety, and high theoretical capacity (820 mAh g−1). However, the lack of cathode materials with long cycle stability severely restricts the development of ZIBs. In this paper, V2O5/ NaV6O15 nanocomposites are synthesized by molten salt method in one step and used as cathode material for ZIBs, which have good electrochemical performances. The specific capacity of the materials remain 160 mAh g−1 when the current density is 0.5 A g−1 after 1000 cycles, and the capacity retention rate is 102.03% when the current density is 5 A g−1 for 1000 cycles. This is mainly due to the large number of active sites generated by crystal defects and the synergistic interaction between the dual-phase materials, which reduces the stress of ions inserted/extracted during the Zn2+ storage process and improves the electrochemical performance.