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

Advanced 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.