Polyaniline-coated sodium vanadate nanorods cathode boosting zinc ion dynamics in aqueous zinc-ion batteries

Abstract

Aqueous zinc batteries (ZIBs) have recently emerged as a promising energy storage system due to their renewability, safety, and cost-effectiveness. However, its electrochemical kinetics are impeded by the issues of low Zn2+ diffusion efficiency and the facile growth of crystalline dendrites in the charging and discharging reactions, which present a significant challenge to the advancement of ZIBs. In this work, a polyaniline (PANI) coated sodium vanadate nanorod-like active material was designed to enhance the ion diffusion efficiency and reduce the tunneling structure collapse of sodium vanadate nanorods. This was achieved by increasing the specific surface area, enhancing the strength of the crystal structure, and introducing oxygen vacancies. The results demonstrated that the PANI-coated sodium vanadate nanorods exhibited stable and highly reversible electrochemical reactions during repeated insertion and extraction of zinc ions. The overall electrochemical performance of the PANI-coated sodium vanadate nanorod electrodes was markedly enhanced, exhibiting a high multiplicity performance of 141 mA/g at a current density of 2.0 A/g and a capacity retention rate of 99.83 % over 5000 cycles. The results provide some information for a better study of Zn2+ storage, as well as ideas for strategies for composite organic polymers with multiple heavy metal hybrid oxides.