N,S co-doped porous carbon with CoS prepared with a Co-FF-derived CoO template: a bi-functional electrocatalyst for rechargeable zinc-air batteries.

To achieve broad commercialization of rechargeable metal-air batteries, the development of non-precious metal-based bi-functional oxygen electrocatalysts is critical. In this study, we prepared N,S co-doped porous carbon materials containing CoS nanoparticles (CoS/NSC) through a one-step pyrolysis process. The process involved the pyrolysis of a polydopamine (PDA) coated Co-formic acid framework (Co-FF) derived CoO and thiourea. The improved catalyst CoS/NSC-1 exhibited satisfactory long-term durability and superior oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity, the half-wave potential () of the ORR reached 0.83 V, and the OER overpotential at 10 mA cm () was 300 mV. The zinc-air battery (ZAB) based on CoS/NSC-1 assembly had a maximum power density of 102.0 mW cm and the cycle life reached 500 cycles. The material preparation method was simple, environmentally friendly and inexpensive, providing a feasible strategy for the development of non-precious metal-based electrocatalysts.