An universal in-situ phosphating strategy to fabricate high-performance Co2P-based bifunctional oxygen electrocatalyst derived from conjugated polyaniline-phytic acid copolymer

Abstract

Electrocatalysts play a crucial role in the performance of rechargeable Zn-air batteries (ZABs), but it is still difficult to produce nonprecious materials with excellent bifunctional oxygen reduction reactions (ORR) and oxygen evolution reactions (OER). Herein, conjugated polyaniline-phytic acid polymer (pANI-PA) was directly calcined to fabricate Co₂P nanoparticles embedded in N, P-doped carbon network composites (Co₂P@pDC-PA) for metal-air cathodes. The resulting pANI-PA derived Co₂P-based carbon composite exhibits exceptional bifunctional ORR/OER activities with a half-wave potential of 0.79 V for ORR and 1.62 V of over-potential for OER at 10 mA·cm⁻². Owing to the synergistic effect of its unique three-dimensional (3D) structure, N, P-doped carbon framework, and encapsulated Co₂P nanoparticles, as-fabricated composite can be used as a highly efficient air cathode in the rechargeable metal-air battery. The assembled rechargeable ZAB demonstrates a high-power density of 190.0 mW·cm⁻² and remarkable cycling stability over 1000 h. This study introduced a novel approach that paves the way for the efficient, cost-effective, and scalable production of bifunctional electrocatalysts for rechargeable ZABs.

Graphical abstract