Interlayer doping of pseudocapacitive hydrated vanadium oxide via Mn2+ for high-performance aqueous zinc-ion battery

Abstract

Zinc-ion batteries suffer from the structural collapse of cathode materials during charge-discharge cycling, making it difficult to achieve long-cycle performance. Interlayer doping of pseudocapacitive vanadium oxide can effectively prevent the structural collapse of cathodes. Herein, an intercalated V-based oxide Mn0.2V8O20·1.12H2O (MnVO) with interlayer water and Mn2+ is synthesized via a hydrothermal method. Mn2+ combines with oxygen in VO6 octahedron of V-based oxides layers to form the solid pillars, so that the V-based oxides provide a large interlayer spacing and prevent the structural collapse of cathode material during charge-discharge processes. This enables the Zn//MnVO battery to output a specific capacity of 306.4 mAh g−1 at 0.1 A g−1. Good cycling stability is achieved with the capacity retention rate of 86.4% after 1000 cycles at 2.0 A g−1. For comparison, the V-based oxide without Mn-doping can only maintain 70.6% after 1000 cycles. The high specific capacity and good cycle stability of MnVO cathode indicate that the Zn//MnVO battery have broad application prospects in the field of energy storage.