Heteroatom-Coordinated Fe–N4 Catalysts for Enhanced Oxygen Reduction in Alkaline Seawater Zinc-Air Batteries

A universal synthetic strategy was proposed to construct heteroatom axially coordinated Fe–N 4 single-atom seawater catalyst materials (Cl–Fe–N 4 and S–Fe–N 4 ). The Cl–Fe–N 4 catalyst achieves a limiting current density of 5.8 mA cm −2 and a half-wave potential of 0.931 V vs. RHE in alkaline synthetic seawater, outperforming commercial Pt/C (40 wt%). The seawater-based zinc-air battery fabricated with Cl–Fe–N 4 demonstrates a power density of 187.7 mW cm −2 at 245.1 mA cm −2 and maintains stable cycling performance for 200 h.