Construction of VOOH/rGO Heterojunction as High‐performance Cathode for Aqueous Zn‐ion Batteries

Abstract Aqueous Zn‐ion batteries (AZIBs) are considered a promising energy storage device due to cost‐effectiveness, high safety, and high theoretical capacities. However, the low reaction kinetics, electron transfer rates, and low energy density cathode materials hinder their practical application on a large scale. In this study, layered VOOH and reduced graphene oxide composites (VOOH/rGO) were synthesized by the hydrothermal method. The design of VOOH/rGO heterojunction could generate the built‐in electric field to accelerate electron transfer and enhance its overall electrical conductivity. Moreover, the enhanced adsorption energy of Zn 2+ on the heterointerfaces is beneficial to stimulate the fast reaction kinetics. And the existence of defects creates the rich diffusion channels that expedite Zn 2+ migration while providing active sites for Zn 2+ storage, as reflected by the impressive electrochemical performance that VOOH/rGO exhibits a specific capacity of 189 mA h g −1 after 280 cycles at a current density of 1 A g −1 . Additionally, it showcases excellent rate performance with a capacity of 225 mA h g −1 at 2 A g −1 , and delivers a capacity of 104 mA h g −1 at 2 A g −1 after 1000 cycles. All the results indicate that VOOH/rGO holds significant potential as a cathode electrode for high‐performance AZIBs.