Co₃O₄–NiCo₂O₄ Hybrid Nanoparticles Anchored on N-Doped Reduced Graphene Oxide Nanosheets as an Efficient Catalyst for Zn–Air Batteries

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).