A Metal‐Free N and P‐Codoped Carbon Nanosphere as Bifunctional Electrocatalyst for Rechargeable Zinc‐Air Batteries

Developing metal‐free electrocatalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial for the large‐scale application of fuel cells and metal‐air batteries, which have attracted extensive attention. Herein, a facile and scalable route is developed to prepare N, P‐codoped carbon nanospheres (NPCs) with the assistance of cesium chloride (NPC‐“Cs”). After treatment with hot acid solution, no trace metals are left in the electrocatalyst, as determined by inductively coupled plasma atom emission spectrometry (ICP‐AES). The obtained metal‐free electrocatalyst exhibits outstanding bifunctional catalytic activity for ORR and OER. The half‐wave potential is 0.85 V for ORR in 0.1 M KOH, and an overpotential of 0.34 V for OER in 1 M KOH is required to reach a current density of 10 mA cm −2 . Furthermore, zinc‐air primary and rechargeable batteries assembled with the metal‐free electrocatalyst show similar, or even better performance compared to precious metal‐based devices containing Pt/C or IrO 2 as catalysts. A facile strategy is developed to synthesize the metal free bifunctional electrocatalyst for ORR and OER that is beneficial for the development of new‐energy technologies.