Phosphate-decorated Fe-N-C to promote electrocatalytic oxygen reaction activities for highly stable zinc-air batteries

An obvious challenge for rechargeable Zn-air batteries (ZABs) is the impact of large charge potentials on the oxidation of their cathode catalysts, which accelerates the corrosion of the carbon electrodes, and significantly compromises their stability. It is therefore necessary to design simple methods aimed at facilitating the oxygen evolution reaction (OER) processes of ZABs to suppress the corrosion of their cathode materials. Herein, a biomass-derived N-doped porous carbon material coupled with Fe3O4 and Fe2N nanoparticles and modified with phosphorus (P-Fe3O4/Fe2N@NPC) was designed as an air-cathode to reduce the charging voltage of ZABs. It exhibited excellent ORR/OER bifunctional electrocatalytic activities, and the assembled ZAB displayed an ultra-long service life. DFT calculations showed that the P-modification modulated the electronic state and coordination environment of the active iron atom, thereby significantly enhancing the OER activity of P-Fe3O4/Fe2N@NPC.