Co, N co-doped carbon nanosheets coupled with NiCo2O4 as an efficient bifunctional oxygen catalyst for Zn-air batteries

Developing of inexpensive and efficient bifunctional oxygen catalysts is important for the zinc-air batteries (ZABs). Here, a composite of Co, N co-doped carbon nanosheets coupled with NiCo2O4 (NiCo2O4/CoNC-NS) is developed as oxygen catalyst, which has good bifunctional oxygen catalytic activity and durability. Specifically, the half-wave potential of oxygen reduction reactions (ORR) is 0.849 V, and the overpotential of oxygen evolution reactions (OER) is 1.582 V at a current density of 10 mA cm-2. And the assembled liquid ZABs based on NiCo2O4/CoNC-NS exhibit high open circuit potential (OCP, 1.482 V), high peak power density (148.3 mW cm-2) and large specific capacity (699.9 mAh g-1) with longterm stability. Moreover, the further assembled solid ZABs can also provide high OCP (1.401 V), good power density (58.1 mW cm-2) and superior stability. This work would provide a good reference for the development of other advanced oxygen catalyst in future. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.