Hydrogel derived N, P co-doped porous defective carbon framework anchored with Co2P nanoparticles as robust electrocatalysts for Zn-air battery

Recently, it is critical but a challenge to exploit economical, high active and stable bifunctional oxygen electrocatalysts for advanced rechargeable Zn-air batteries (ZABs). Herein, a robust ORR/OER electrocatalyst (Co2P/ H-NPC) was prepared using Co2P nanoparticles (NPs) anchored on a N,P-doped three-dimensional (3D) hierarchically porous carbon framework with rich defects through carbonizing a hydrogel, involving starch, polyinosinic acid, cobalt(II) acetate and NH4Cl. Co2P NPs and the dual doping of heteroatoms (N and P), as well as the hierarchically porous feature, synergistically endow Co2P/H-NPC with an excellent ORR and OER activities, in terms of positive half-wave potential (0.83 V) and low overpotential (390 mV) at a current density of 10 mA cm -2, respectively. Additionally, the assembled ZAB based on Co2P/H-NPC delivers a peak power density of 120 mW cm -2, and a wonderful discharge-charge cycling stability, indicating good potential for further application in the fields of energy storage and conversion devices.