Oxygen vacancy H2V3O8 nanowires as high-capacity cathode materials for aqueous zinc-ion batteries

Abstract

Abstract H2V3O8 has been regarded as a compelling cathode material for aqueous zinc-ion batteries (AZIBs) owing to its elevated theoretical capacity, abundance of vanadium valence states, and advantageous layered configuration. Nonetheless, the intrinsically low conductivity and sluggish ionic reaction kinetics of H2V3O8 result in undesirable, constraining its broader implementation in AZIBs. In this study, a facile hydrothermal approach was utilized to prepare H2V3O8 nanowires with an abundance of oxygen vacancies. The combination of nanowire nanostructure and oxygen vacancies of the H2V3O8 offer improved ion diffusion kinetics and enhanced electronic conductivity, leading to a superior improved electrochemical performance. Particularly, the H2V3O8 nanowire cathodes with the optimal oxygen vacancy concentration (HVO-20) exhibit a specific capacity of 461.7 mAh g− 1 at 0.3 A g− 1 and exceptional cycle life of 198.8 mAh g− 1 after 1000 cycles at 1.0 A g− 1. The investigation unveils the impact of oxygen vacancy vanadium-based oxides on the performance of AZIBs, presenting a viable strategy for advanced cathode materials in AZIBs.