Pyridine Nitrogen Decorated Carbon Support for High-Performance Seawater Electrolyte-Based Zinc-Air Battery

Developing high specific energy seawater electrolyte-based zinc-air batteries (SZABs) is crucial for marine energy supply systems. However, their widespread application is restricted by the slow oxygen reduction reaction (ORR) kinetics coupled with the poisoning of adsorbed Cl^- in seawater electrolyte. Herein, we design a pyridinic nitrogen-modified carbon-supported Fe single-atom catalyst [Fe-SAC/NC(Py)] to achieve exceptional ORR performance in seawater electrolytes. The Fe-SAC/NC(Py) achieves a high onset potential (E_onset) and halfwave potential (E_1/2) of 1.174 and 0.907 V versus RHE, respectively, significantly outperforming the commercial 20% Pt/C (E_onset: 0.972 V, E_1/2: 0.848 V). Furthermore, the assembled SZABs demonstrates a peak power density of 204 mW cm^-2 and a specific capacity of 800 mAh g^-1, surpassing most previously reported catalysts. In-situ characterizations and theoretical calculations reveal that the pyridinic nitrogen-modified carbon support in situ constructs a negatively charged interface during ORR process, effectively suppressing Cl^- adsorption. Additionally, the atomic Fe sites coordinated with pyridinic nitrogen optimize the charge distribution of the active centers, lowering the adsorption energy of oxygen-containing intermediates and thereby enhancing ORR catalytic performance.