Core-shell-structured NiCo2O4 composite with GO/C to enhance its electrocatalytic performance as a cathode catalyst in zinc-air batteries

Abstract

This study employed a simple and effective method to synthesize a composite material comprising core-shell NiCo2O4 and GO/C. The combination of core-shell NiCo2O4 and GO effectively improved the poor conductivity of NiCo2O4 and prevented the aggregation of NiCo2O4 microspheres. In electrochemical tests, compared to pure core-shell NiCo2O4, NiCo2O4@GO/C exhibits improved catalytic performance in both oxygen reduction (ORR) and oxygen evolution reactions (OER). Its OER catalytic performance is notably superior to that of noble metal catalysts. The NiCo2O4@GO/C-based liquid-state zinc-air battery exhibited a stable cycling efficiency of 51% over 200 h of charge-discharge cycles, significantly outperforming precious metal-based batteries. Additionally, a flexible quasi-solid-state zinc-air battery, assembled with the NiCo2O4@GO/C composite material as the cathode catalyst, exhibited an outstanding cycling efficiency of 58% in charge-discharge cycles. These results indicate that the NiCo2O4@GO/C composite material holds great potential as a bifunctional electrocatalytic catalyst for zinc-air batteries.