Co<sub>3</sub>O<sub>4</sub>–NiCo<sub>2</sub>O<sub>4</sub> Hybrid Nanoparticles Anchored on N-Doped Reduced Graphene Oxide Nanosheets as an Efficient Catalyst for Zn–Air Batteries
Zhaogen Zhu, Jinming Zhang, Xiaomin Peng, Yiyi Liu, Tianlun Cen, Zhifeng Ye, Dingsheng Yuan
Abstract
Developing efficient bifunctional electrocatalysts with excellent oxygen reduction and evolution reaction (ORR/OER) activity to meet practical demands in Zn–air batteries (ZABs) is highly crucial and challenging. Herein, a simple hydrothermal one-step method is exploited to successfully synthesize Co3O4–NiCo2O4 anchored on N-doped reduced graphene oxide nanosheets (Co3O4–NiCo2O4/N-RGO). The active sites present in Co3O4–NiCo2O4/N-RGO and the synergy between N-RGO and Co3O4–NiCo2O4 accelerate the charge transfer and transport rate during the electrochemical course, which improves the ORR/OER activities of the Co3O4–NiCo2O4/N-RGO electrocatalyst. As expected, the Co3O4–NiCo2O4/N-RGO exhibits a better half-wave potential in the ORR and a lower Tafel slope during the OER process. A ZAB with optimal Co3O4–NiCo2O4/N-RGO as the cathode gives a higher open-circuit voltage (1.49 V), larger power density (97 mW cm–2), and better stability (180 h).