Cobalt-decorated defective carbon paper as a self-supported catalyst for oxygen electrocatalysis and rechargeable zinc-air battery.

Carbon-supported transition-metal materials have been recognized as efficient bifunctional electrocatalysts for oxygen evolution/reduction reactions (OER/ORR) in rechargeable zinc-air batteries. While the pursuit of high-performance catalysts remains critical, the industrial applications of catalysts and their synthesis methods cannot be ignored. In this work, a self-supported hybrid catalyst is prepared by anchoring cobalt oxide particles on defective carbon papers. Commercial carbon papers were first treated by nitrogen plasma to introduce surface defects and increase their surface hydrophilicity, thereby facilitating the subsequent cobalt deposition. The resulting catalyst with abundant carbon defects and deposited Co oxide particles exhibits an increased number of active sites and improved surface conductivity compared to pristine carbon papers, leading to enhanced bifunctional electrocatalytic performance. When employed in a liquid zinc-air battery, this catalyst shows acceptable discharging and charging potentials, along with a higher durability than the battery utilizing a mixed noble metal-based catalyst. Our findings represent a novel and large-scale application strategy for synthesizing self-supported carbon-supported transition-metal materials for rechargeable zinc-air batteries and associated energy storage systems.