Ultra-long Zn3V2O7(OH)2·2H2O nanowires grown on carbon cloth as cathode material for aqueous zinc-ion batteries

Abstract

Enhancing the performance of the cathode materials is one of the key issues for aqueous zinc-ion batteries (AZIBs). Layered vanadium-based compounds are considered to be a candidate cathode material for AZIBs owing to their advantages of variable crystal structures and high-theoretical capacity. Nevertheless, the inherent low conductivity of V-based compounds leads to their sluggish kinetics and serious capacity degradation of AZIBs. Here, we proposed a strategy that combined morphology regulation with self-supporting electrodes to build an efficient electron/ion transport network and prepared Zn3(OH)2V2O7·2H2O (ZVO) nanowires (ZVNW) on carbon cloth (CC) by a hydrothermal method. As expected, the ZVNW-CC electrode showed excellent electrochemical performances of a high specific capacity of 361.8 mAh g-1 (50 mA g-1), high-rate capability (145.9 mAh g-1 discharge capacity at 1,000 mA g-1), and long cycling life (96.7% capacity retention after 1010 cycles at 1,000 mA g-1). The Zn2+/H2O co-intercalation mechanism for ZVNW-CC electrodes was demonstrated by ex-situ XPS and ex-situ TGA.