Integration of Fe<sub>3</sub>C and Fe<sub>3</sub>P\nNanoparticles Anchored on N‑Doped Carbon as Bifunctional Oxygen\nCatalysts for Rechargeable Zn-Air Batteries

Exploiting highly active bifunctional earth-abundant\ntransition\nmetal electrocatalysts for the oxygen reduction reaction (ORR) and\noxygen evolution reaction (OER) is of great importance for rechargeable\nZn-air batteries. Herein, an in situ pyrolysis strategy was employed\nto integrate Fe<sub>3</sub>C and Fe<sub>3</sub>P nanoparticles anchored\non N-doped carbon ((Fe<sub>3</sub>C, Fe<sub>3</sub>P)/NC) electrocatalyst.\nThe strong synergistic effect between Fe<sub>3</sub>C and Fe<sub>3</sub>P had a significant beneficial impact in improving the graphitization\ndegree, enlarging the specific surface area and pore volume. Besides\nthat, the electron migration between N and Fe sites and electron redistribution\non the two components endow (Fe<sub>3</sub>C, Fe<sub>3</sub>P)/NC\nwith prominent bifunctional oxygen catalytic performance toward ORR\nand OER (Δ<i>E</i> = 0.88 V), superior to that of\nthe Fe<sub>3</sub>C/NC, Fe<sub>3</sub>P/NC. Furthermore, the (Fe<sub>3</sub>C, Fe<sub>3</sub>P)/NC-based rechargeable Zn-air battery also\nshows high peak power density (159.54 mW·cm<sup>–2</sup>), specific capacity (731.42 mAh·g<sub>Zn</sub><sup>–1</sup>), energy density (852.10 Wh·kg<sub>Zn</sub><sup>–1</sup>), and stability.