In situ formation of self‐antistacking FeCoO_x 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 (FeCoO_x) are directly grown on 2D N‐doped graphene (NG). The in situ grown FeCoO_x 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, FeCoO_x@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%‐FeCoO_x@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.