Integration of Fe₃C and Fe₃P Nanoparticles Anchored on N-Doped Carbon as Bifunctional Oxygen Catalysts for Rechargeable Zn-Air Batteries

Exploiting highly active bifunctional earth-abundant transition metal electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is of great importance for rechargeable Zn-air batteries. Herein, an in situ pyrolysis strategy was employed to integrate Fe3C and Fe3P nanoparticles anchored on N-doped carbon ((Fe3C, Fe3P)/NC) electrocatalyst. The strong synergistic effect between Fe3C and Fe3P had a significant beneficial impact in improving the graphitization degree, enlarging the specific surface area and pore volume. Besides that, the electron migration between N and Fe sites and electron redistribution on the two components endow (Fe3C, Fe3P)/NC with prominent bifunctional oxygen catalytic performance toward ORR and OER (ΔE = 0.88 V), superior to that of the Fe3C/NC, Fe3P/NC. Furthermore, the (Fe3C, Fe3P)/NC-based rechargeable Zn-air battery also shows high peak power density (159.54 mW·cm–2), specific capacity (731.42 mAh·gZn–1), energy density (852.10 Wh·kgZn–1), and stability.