In situ formation of self‐antistacking FeCoOx on N‐doped graphene: A 3D‐on‐2D nanoarchitecture for long‐life Zn–air batteries

Abstract Before the practical application of rechargeable Zn–air batteries (ZABs), a critical issue regarding the inherent slow reaction kinetics of the oxygen reduction (ORR) and oxygen evolution (OER) must be addressed. Here, we fabricate a cost‐effective bifunctional oxygen electrocatalyst with a self‐antistacking structure, where three‐dimensional (3D) Fe–Co bimetallic oxide particles (FeCoOx) are directly grown on 2D N‐doped graphene (NG). The in situ grown FeCoOx particles can alleviate the NG interlaminar restacking, ensuring abundant channels for diffusion of O2/OH− species, while the NG allows rapid electron flow. Benefiting from this self‐antistacking 3D‐on‐2D structure and synergetic electrocatalysis, FeCoOx@NG demonstrated excellent activity for both ORR and OER (ΔE = 0.78 V), which is superior to that of the binary mixtures of Pt/C and RuO2 (ΔE = 0.83 V). A homemade ZAB with 20%‐FeCoOx@NG delivers a specific capacity of 758.9 mAh g−1, a peak power density of 215 mW cm−2, and long‐term cyclability for over 400 h. These research results suggest that designing a bimetallic oxide/N‐doped carbon 3D‐on‐2D nanoarchitecture using an in situ growth strategy is an attractive and feasible solution to overcome electrocatalytic problems in ZABs.