Current Collector Design Principle for Long-Cycling Aqueous Zinc Batteries With Minimal Anode Usage

Zinc (Zn)-based aqueous electrochemical systems promise low-cost, high safety, and simplicity, yet they struggle with poor rechargeability due to dendritic Zn growth. The root cause of dendrite formation and poor utilization of Zn electrodes is identified as the competitive hydrogen evolution reaction (HER) and its co-deposition of insulating side-products, the latter deteriorating both the nucleation and growth of Zn electrodeposition. By investigating the effect of substrate materials, we classified the thermodynamic and kinetic effects of both HER and Zn reduction and their influence on Zn reversibility. Benefitting from this guideline, we developed a multifunctional graphite-coated copper current collector that significantly suppresses HER while maintaining good affinity with Zn deposition. The substrate design enhances Zn reversibility to 99.95% with 1-time excessive Zn design, and endows an aqueous Zn//AC supercapacitor with over 400 000 cycles and a high-areal-capacity Zn-MnO₂ battery with a low N/P ratio.