Defective Fe<sub>3</sub>O<sub>4‐</sub><i><sub>x</sub></i> Few‐Atom Clusters Anchored on Nitrogen‐Doped Carbon as Efficient Oxygen Reduction Electrocatalysts for High‐Performance Zinc–Air Batteries
Panpan Chu, Yingmeng Zhang, Jiajie He, Jinhong Chen, Jingjun Zhuang, Yongliang Li, Xiangzhong Ren, Peixin Zhang, Lingna Sun, Bingzhe Yu, Shaowei Chen
Abstract
Abstract It remains a challenge to develop cost‐effective, high‐performance oxygen electrocatalysts for rechargeable metal–air batteries. Herein, zinc‐mediated zeolitic imidazolate frameworks are exploited as the template and nitrogen and carbon sources, onto which is deposited a Fe 3 O 4 layer by plasma‐enhanced atomic layer deposition. Controlled pyrolysis at 1000 °C leads to the formation of high density of Fe 3 O 4‐ x few‐atom clusters with abundant oxygen vacancies deposited on an N‐doped graphitic carbon framework. The resulting nanocomposite (Fe 3 O 4‐ x /NC‐1000) exhibits a markedly enhanced electrocatalytic performance toward oxygen reduction reaction in alkaline media, with a remarkable half‐wave potential of +0.930 V versus reversible hydrogen electrode, long‐term stability, and strong tolerance against methanol poisoning, in comparison to samples prepared at other temperatures and even commercial Pt/C. Notably, with Fe 3 O 4‐ x /NC‐1000 as the cathode catalyst, a zinc–air battery delivers a high power density of 158 mW cm −2 and excellent durability at 5 mA cm −2 with stable 2000 charge–discharge cycles over 600 h. This is ascribed to the ready accessibility of the Fe 3 O 4‐ x catalytic active sites, and enhanced electrical conductivity, oxygen adsorption, and electron‐transfer kinetics by surface oxygen vacancies. Further contributions may arise from the highly conductive and stable N‐doped graphitic carbon frameworks.