High-loading and high-performance zinc ion batteries enabled by electrochemical conversion of vanadium oxide cathodes

Abstract

Zinc ion batteries (ZIBs) have become highly competitive in large-scale energy storage applications due to their safety, low cost, and environmental friendliness. However, the cathode materials reported in the literature have the problem of low load (generally less than 3 mg cm‒2), which is difficult to meet the needs of industrial production. In this study, a three-dimensional network structure of calcium ion intercalated vanadium oxide cathode (CaVOH) is grown on carbon cloth (CC) by the one-step hydrothermal method. The cathode has a unique three-dimensional network structure and high mass load (∼ 7 mg cm‒2), high specific capacity (228.5 mAh g‒1 at 1 A g‒1 current density), excellent rate performance, and qualified cycle performance (70 % residual after 800 cycles). In Zn(CF3SO3)2 electrolyte, CaVOH@CC is transformed into Zn2(V3O8)2@CC (ZVO@CC) cathode by electrochemical induction. Compared with vanadium oxide cathode synthesized on carbon cloth (VOH@CC), ZVO@CC cathode has lower charge transfer resistance and higher capacitance contribution, which means that it has a better specific capacity, rate performance, and cycle stability. This work provides a new idea for the mechanical explanation of ZIB and a feasible scheme for the design of industrial ZIBs.