Reduced graphene oxide aerogel-supported Fe-ZIF-67/ZIF-8 enables scalable synthesis of high-performance bifunctional catalysts for zinc–air batteries

Abstract

The performance of zinc–air batteries (ZABs) is often hindered by the limited activity and sluggish kinetics of bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this work, a high-performance bifunctional catalyst (FeCo-NC@rGO) was synthesized by anchoring ZIF-derived Co_5.47N and CoFe nanoparticles (NPs) onto a reduced graphene oxide (rGO) aerogel, accompanied by in situ growth of carbon nanotubes (CNTs). The M–N–C sites within the carbon matrix provide abundant ORR active centers, while Co_5.47N and CoFe NPs impart excellent OER activity. As a result, FeCo-NC@rGO exhibits a high ORR half-wave potential of 0.85 V (vs. RHE) and a low OER overpotential of 400 mV at 10 mA cm⁻², outperforming Pt/C (0.82 V) and RuO₂ (508 mV), respectively. A liquid ZAB using this catalyst achieves an open-circuit voltage of 1.51 V, a power density of 114.6 mW cm⁻², a specific capacity of 838.2 mAh g⁻¹, and stable cycling for 250 h. The solid-state ZAB also demonstrates strong performance with excellent durability. This study provides an effective and scalable strategy for developing advanced bifunctional electrocatalysts for high-performance ZABs.