NiFeMo nanoparticles encapsulated within nitrogen-doped reduced graphene oxide as bifunctional electrocatalysts for zinc-air batteries

Abstract

Rechargeable metal-air batteries (MABs) have emerged as promising candidates for portable energy storage technologies because of their favorable energy/power density, safety, and cost-effectiveness. However, the lack of advanced bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) restricts the commercial realization of rechargeable MABs. Herein, we developed a facile fabrication route to prepare N-doped graphene oxide encapsulating nanoparticles of a ternary NiFe metal oxide (NiFeMo@N-rGO) serving as an efficient bifunctional catalyst. The obtained NiFeMo@N-rGO bifunctional catalyst demonstrates a comparable catalytic reactivity when compared to precious metal catalysts in alkaline electrolytes regarding ORR/OER performance (ORR: half-wave potential of 0.82 V; OER: overpotential of 330 mV; E: 0.73 V at 10 mA cm(-2)). The assembled zinc-air batteries (ZABs) catalyzed by NiFeMo@N-rGO exhibit a high power density of 120 mW cm(-2) and a capacity of 721 mAh g(Zn)(-1), coupled with long-term durability of over 200 h. This contribution paves a practical avenue to prepare efficient bifunctional catalysts for superior ZABs.