Fabrication of a Porous Electrocatalyst Based on Fe, N, S Co-Doped Carbon Nanosheets for Zinc-Air Batteries

Abstract Developing oxygen reduction reaction (ORR) catalysts with high efficiency and stability represents a key requirement for zinc-air batteries. Employing a mixture of iron nitrate nonahydrate, citric acid, and ammonium persulfate as precursors and g-C3N4 as a sacrificial template, this study synthesized Fe, N, S co-doped porous carbon nanosheets via ball-milling and one-step pyrolysis, offering a solvent-free and simple process. In alkaline electrolyte, Fe-NSC 1000 exhibited outstanding ORR performance, showing onset and half-wave potentials of 1.00 and 0.896 V, respectively. Fabricated into the cathode of a zinc-air battery, it offered outstanding durability (up to 1025 h at 5 mA cm–2) in addition to a specific capacity of 760.65 mA h gZn–1 and a peak power density of 145.65 mW cm–2. This work provides a simpler and greener strategy for designing iron-based sulfur-doped ORR catalysts, driving forward zinc-air battery technology.