Monolithic Co-N-C membrane integrating Co atoms and clusters as a self-supporting multi-functional electrode for solid-state zinc–air batteries and self-powered water splitting

Abstract

For practical applications in electrochemical devices such as zinc air batteries and alkaline water electrolyzers, an efficient electrode design with satisfactory multifunctional catalytic activity is a pivotal prerequisite. Herein, a self-supporting monolithic electrode for electrocatalyst-based devices with exceptionally high multi-functional catalytic activity is presented. The optimized tri-functional activity is recorded at a current density of 10 mA cm−2 with an overpotential at 36 mV for HER, and 229 mV for OER, indicating 1.51 V in an alkaline water electrolyzer, as well as a half-wave potential of 0.858 V for ORR. More importantly, the catalyst electrode exhibits an extremely low charge–discharge potential gap (ΔE less than 0.5 V) in solid-state rechargeable zinc-air batteries, attributed to its monolithic characteristics. Consequently, a self-powered hydrogen production system is driven by the identical pieces of the CoNC monoliths and zinc foil as a power source.