Effects of current density on Zn reversibility

Abstract

Aqueous zinc (Zn) batteries (AZBs) exhibit potential as viable candidates for stationary energy storage. Improvements in the plating/stripping efficiency and lifespan of Zn anodes at high applied current density (j) render AZBs attractive for rapid charge and discharge scenarios. However, the existing literature presents inconsistent experimental results and interpretations regarding the impact of j on Zn reversibility. While some studies indicate that increasing j reduces Zn reversibility, others argue the opposite. In this perspective, we delve into this conflicting phenomenon with a specific focus on the fundamentals of Zn electrodeposition, nucleation-growth models and theories related to j, and future development. Our stance supports the notion that an increase in j leads to a volcano-shaped pattern in the reversibility of Zn plating and stripping, and such a relationship lies in the dual and contradictory roles that high j plays in thermodynamics and interfacial kinetics. Our in-depth discussion provides valuable insights for accurate data interpretation and holds significant promise for advancing high-power AZBs.