Electronic Tuning of Core–Shell CoNi Nanoalloy/N-Doped Few-Layer Graphene for Efficient Oxygen Electrocatalysis in Rechargeable Zinc–Air Batteries
Jinlong Liu, Ziyu Luo, Dong Qian, Lishan Peng, Dongxiao Sun‐Waterhouse, Geoffrey I. N. Waterhouse
Abstract
The discovery of highly efficient, durable, and affordable bifunctional ORR/OER electrocatalysts is of great significance for the commercialization of rechargeable metal–air batteries. Herein, we synthesized uniformly sized CoNi alloy nanoparticles encapsulated with N-doped few-layer graphene (N-FLG) sheets via pyrolysis of a CoNi dual metal–organic framework precursor. The developed CoNi/N-FLG catalyst exhibited excellent oxygen reduction activity (comparable to a commercial 20 wt % Pt/C catalyst) and outstanding oxygen evolution activity (superior to a commercial 20 wt % IrO2/C catalyst), thus enabling efficient bifunctional oxygen electrocatalysis and stability when applied in prototype rechargeable zinc–air batteries. The remarkable electrochemical properties of CoNi/N-FLG originate from its unique core–shell structure and favorable electron penetration effects, thereby optimizing the adsorption/desorption strengths of intermediates formed during the oxygen reduction and oxygen evolution reactions.