Biomass-Derived Carbon-Coated FeCo Alloys as Highly Efficient Bifunctional Electrocatalyst for Rechargeable Zinc–Air Batteries

The development of highly effective bifunctional electrocatalysts for the oxygen reduction (ORR) and evolution reactions (OERs) is pivotal for the advancement of rechargeable zinc–air batteries (ZABs) with superior electrochemical performance. This study presents a facile strategy for the synthesis of a biomass-derived nitrogen-doped carbon-coated FeCo catalyst. By optimizing the calcination temperature, the FeCo@NC-900, synthesized at 900 °C, demonstrates superior ORR/OER performance, with a half-wave potential of 0.81 V for ORR and an overpotential of 349 mV to drive a current density of 10 mA cm–2 for OER. Electrochemical testing of ZABs employing FeCo@NC-900 as electrode catalysts reveals excellent performance, with a peak power density of 103.6 mW cm–2 at 160 mA cm–2 and sustains operation for over 300 h at a current density of 5 mA cm–2 with superior cycling stability. These results surpass those of the Pt/C-RuO2-based counterpart. Given its low cost and straightforward preparation, FeCo@NC-900 emerges as a highly promising catalyst for energy storage and conversion applications.