CoFe-FF derived CoFe alloy@N,P-doped carbon composites: preparation and zinc–air battery performance evaluation

Abstract

Developing efficient bifunctional catalysts for air cathodes is crucial for enhancing the performance of zinc–air batteries (ZABs). In this study, we synthesized N,P-codoped carbon-coated CoFe alloy nanoparticles (CoFe@NPC-1) using a one-step high-temperature pyrolysis method. The precursor was a cobalt–iron formic acid framework (CoFe-FF), while dicyandiamide served as the nitrogen source and phytic acid as the phosphorus source. The resulting electrocatalyst exhibited a half-wave potential of 0.83 V in 0.1 M KOH for the oxygen reduction reaction (ORR) and an overpotential of 310 mV for the oxygen evolution reaction (OER) in 1 M KOH. A zinc–air battery assembled with a CoFe@NPC-1 air cathode demonstrated an open-circuit voltage of 1.40 V and a specific capacity of 700.8 mAh g⁻¹, showcasing superior durability compared to the Pt/C + RuO₂ catalyst. The satisfactory bifunctional catalytic activity of this simple composition can be attributed to the synergistic effect between the N and P elements, which effectively regulate the electrons around carbon atoms, as well as the bimetallic CoFe alloy. This study provides novel methods and insights for synthesizing CoFe alloy N,P-doped porous carbon composites as highly efficient electrocatalysts for the oxygen reduction reaction.