I <sub>3</sub> <sup>−</sup> ‐Mediated Oxygen Evolution Activities to Boost Rechargeable Zinc‐Air Battery Performance with Low Charging Voltage and Long Cycling Life
Xiaohong Zou, Qian Lü, Lizhen Wu, Kouer Zhang, Mingcong Tang, Haijiao Xie, Xiao Zhang, Zongping Shao, Liang An
Abstract
Abstract An effective strategy to facilitate oxygen redox chemistry in metal‐air batteries is to introduce a redox mediator into the liquid electrolyte. The rational utilization of redox mediators to accelerate the charging kinetics while ensuring the long lifetime of alkaline Zn‐air batteries is challenging. Here, we apply commercial acetylene black catalysts to achieve an I 3 − ‐mediated Zn‐air battery by using ZnI 2 additives that provide I 3 − to accelerate the cathodic redox chemistry and regulate the uniform deposition of Zn 2+ on the anode. The Zn‐air battery performs an ultra‐long cycle life of over 600 h at 5 mA cm −2 with a final charge voltage of 1.87 V. We demonstrate that I − mainly generates I 3 − on the surface of carbon catalysts during the electrochemically charging process, which can further chemically react with OH − to generate oxygen and further revert to I − , thus obtaining a stable electrochemical system. This work offers a strategy to simultaneously improve the cycling life and reduce the charging voltage of Zn‐air batteries through redox mediator methods.