Inhibiting Demetalation of Fe─N─C via Mn Sites for Efficient Oxygen Reduction Reaction in Zinc‐Air Batteries
Chuan Hu, Gengyu Xing, Wentao Han, Yixin Hao, Chenchen Zhang, Ying Zhang, Chun‐Han Kuo, Han‐Yi Chen, Feng Hu, Linlin Li, Shengjie Peng
Abstract
Abstract Demetalation caused by the electrochemical dissolution of metallic Fe atoms is a major challenge for the practical application of Fe─N─C catalysts. Herein, an efficient single metallic Mn active site is constructed to improve the strength of the Fe─N bond, inhibiting the demetalation effect of Fe─N─C. Mn acts as an electron donor inducing more delocalized electrons to reduce the oxidation state of Fe by increasing the electron density, thereby enhancing the Fe─N bond and inhibiting the electrochemical dissolution of Fe. The oxygen reduction reaction pathway for the dissociation of Fe─Mn dual sites can overcome the high energy barriers to direct O─O bond dissociation and modulate the electronic states of Fe─N 4 sites. The resulting FeMn─N─C exhibits excellent ORR activity with a high half‐wave potential of 0.92 V in alkaline electrolytes. FeMn─N─C as a cathode catalyst for Zn‐air batteries has a cycle stability of 700 h at 25 °C and a long cycle stability of more than 210 h under extremely cold conditions at −40 °C. These findings contribute to the development of efficient and stable metal‐nitrogen‐carbon catalysts for various energy devices.