Critical metrics for practical application-oriented rechargeable zinc-air batteries

Abstract

The application of rechargeable zinc-air batteries (RZABs) is hindered by sluggish oxygen reaction kinetics at air electrodes and poor reversibility of zinc electrodes. This work analyzes the fundamental issues limiting the practical implementation of RZABs and proposes a practical application-oriented performance evaluation framework. For air electrodes, in-situ gas monitoring techniques are critically needed to accurately distinguish the electrochemical reaction pathways during the charging process of transition metal catalysts and the competitive mechanisms between carbon corrosion and oxygen evolution reactions. With respect to zinc electrodes, conventional low depth of discharge (DOD) testing conditions mask irreversible capacity loss under practical high-DOD (>20 %) operation, necessitating the establishment of a “limited zinc-high DOD” system to reliably assess electrode performance. Furthermore, full-cell design requires optimization of key parameters. The standardized evaluation framework proposed herein not only provides critical guidance for the industrialization of RZABs but also can be extended to other metal-air battery systems.