N-, S-Codoped Porous Carbon With Trace Single-Atom Fe for Enhanced Oxygen Reduction With Robust Poison Resistance and Efficient Rechargeable Zinc–Air Battery

Abstract

Pt-based electrocatalysts in oxygen reduction reaction (ORR) have severely hindered large-scale application of relevant energy technologies. Carbon composites codoped with heteroatoms and transition metals are considered the most likely alternatives to Pt, but they still have the limitation of poor tolerance to poisons. Thus, exploration of advanced electrocatalysts with superior activity and high poison resistance is of great significance in practical applications. Herein, a low-cost lysozyme was first directly used to fabricate single-atomic Fe anchored on porous N-, S-codoped carbon (Fe-PNSC) using a simple “mix-and-pyrolyze” method, which has a honeycomb-like porous structure with a large surface area of 957.69 m²/g, adequate pores of 0.71 cm³/g, and rich heteroatom doping of 4.66 at.% N, 1.9 at.% S, and 0.18 wt.% single-atomic Fe. Accordingly, Fe-PNSC displays an onset potential of 1.08 V and a half-wave potential of 0.86 V for ORR, strong stability with 96.87% current retention, and robust resistance to methanol and various poisons, all outperforming Pt/C. Additionally, the Fe-PNSC–based zinc–air battery shows a high peak power density of 122.2 mW cm⁻², good specific capacity and energy density of 787 mAh g_Zn⁻¹ and 975.9 Wh kg_Zn⁻¹, respectively, and remarkable rechargeable stability for 300 h, superior to Pt/C-based ones.