Flower-like NiCo2O4-CN as efficient bifunctional electrocatalyst for Zn-Air battery

Bifunctional transition metal oxide based electrocatalysts play an important role in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for rechargeable metal-air batteries. Herein, we synthesize a kind of three-dimensional (3D) flower-like composite catalyst with NiCo2O4 and N doped carbon (NC) derived from g-C3N4, under hydrothermal conditions. The best NiCo2O4-CN catalyst shows a hierarchical structure composed of interconnected nanosheets, and exhibits versatile bifunctional ORR/OER electroactivities with a half-wave potential of 0.81 V for ORR and an overpotential of 383 mV for OER under a current density of 10 mA cm(-2). The zinc-air battery with the NiCo2O4-CN cathode demonstrates superior peak power density (149.6 mW cm(-2)), excellent capacity performance up to 738.7 mAh g(-1) and considerable durability, showing the feasibility of NiCo2O4-CN in electrochemical energy devices. (C) 2020 Published by Elsevier Ltd.