Stabilizing Zn anode for high-performance Zn-Ni battery through a complexing agent electrolyte addition

Zn-Ni batteries have garnered considerable attention due to their high specific energy, consistent discharge voltage, favorable performance at low temperatures, and environmentally benign nature. Nevertheless, anode interface issues such as dendrite growth, hydrogen evolution, and interfacial side reactions lead to poor cycling stability of Zn-Ni batteries, significantly limiting their further commercial applications. In this study, we propose a facile electrolyte engineering strategy to optimize the Zn anode interfacial environment and stabilize the Zn anode by introducing tannic acid (TA) into the KOH electrolyte. The incorporated TA complexing agent addition will be used to prevent the direct contact of H2O with the anode surface and promote the desolvation of Zn2+ through complexation, thus suppressing the interfacial corrosion. Consequently, the Zn symmetric battery using TA electrolyte cycles stably for 178 h at 1 mA cm-2. The Zn-Ni full batteries with TA electrolyte maintain 98.08 % capacity retention after 2000 cycles at 20C. This study will be of immediate benefit in commercializing large-scale, practical energy storage applications.