MOF-derived FeCo-NC@Co2P-NC as a high-performance bifunctional electrocatalyst for rechargeable Zn-Air batteries

Low-cost, highly stable, and high-performance non-precious metal bifunctional oxygen reduction/oxygen evolution reaction (ORR/OER) electrocatalysts ensure the large-scale commercialization of rechargeable Zn-air batteries. In this study, we obtained an efficient bifunctional electrocatalyst (FeCo-NC@Co2P-NC) using pyrolysis and subsequent phosphorylation of ZIF-67 after the addition of an iron source. The excellent ORR activity is primarily attributed to the FeCo-NC sites, while Co2P is the active site for high-performance OER. Therefore, the obtained FeCo-NC@Co2P-NC has high onset and half-wave potentials for the ORR and a low overpotential for the OER, indicating its excellent bifunctional activity. It exhibited a reversible oxygen overpotential that exceeded that of commercial Pt/C and RuO2. In addition, the Zn-air battery with the FeCo-NC@Co2P-NC catalyst had a high peak power density and cycling stability, exhibiting better performance than the commercial 20 % Pt/C-RuO2. Therefore, this study provides a new strategy for the rational design of efficient non-precious metal electrocatalysts for energy storage and conversion. (c) 2022 Elsevier B.V. All rights reserved.