Hierarchically Structured Co(OH)₂/CoPt/N-CN Air Cathodes for Rechargeable Zinc–Air Batteries

For the realization of the large-scale deployment of rechargeable Zn–air batteries, it is crucial to develop cost-effective, efficient, and stable bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this work, an integrated electrocatalyst consisting of Co(OH)2/CoPt/N-CN was developed to enable both ORR and OER reactions for Zn–air batteries. The hierarchical Co(OH)2/CoPt/N-CN electrocatalyst has desirable electrochemical properties, with comparable activity and better durability than commercial Pt/C for ORR and improved activity and long-term stability than commercial IrO2 catalyst for OER. When implemented as air–cathode for rechargeable Zn–air batteries, Co(OH)2/CoPt/N-CN exhibited a high power-density of 171 mW cm–2, a specific capacity of 812 mA h g–1, and a robust cycling life. Interestingly, the hierarchical structure remained intact upon charge and discharge tests, suggesting potential long-term use in the Zn–air battery technology. The material development strategy presented here can enrich the toolbox for the design and construction of cost-effective, efficient, and robust bi-functional electrocatalysts for ORR and OER toward rechargeable Zn–air battery applications.