Water Invoking Interface Corrosion: An Energy Density Booster for Ni//Zn Battery

Abstract

AbstractAdvanced Ni//Zn batteries possess great promise that combines battery‐level energy density and capacitor‐level power density. However, the surface chemical reactivity of the cathode is generally restricted by active material utilization, leading to an insensitive edge site and unsatisfactory capacity. Herein, a simple and energy‐saving strategy is reported for manipulating the bimetallic sulfide nanointerfaces via water invoking interface corrosion to achieve a 200% increase in the capacity of electrodes. The combined action of water and oxygen causes secondary in situ growth of NiCo–OH nanosheet coating layers on the CoxNi3‐xS2 nanowalls with surface enrichment of low‐valence mixed states, which deliver remarkable reactive activity and structural stability. As a result, the 3D cathode yields an ultrahigh capacity of 2.45 mAh cm−2, higher than that of the pristine nanomaterial (1.20 mAh cm−2). The resulting Ni//Zn battery with excellent reversibility and long‐life, achieves a remarkable energy density of 4.29 mWh cm−2 (728 Wh kg−1), which is superior to most recently reported aqueous Zn‐based batteries and is even comparable to Li‐ion batteries. This work explores the interface corrosion mechanism and corrosion‐surface activity relationship, which is a powerful strategy to construct high surface electrochemical activity of metallic sulfides/phosphides for renewable energy storage devices.