A Redox-Mediated Zinc–Air Fuel Cell

Zinc-air batteries (ZABs) have recently attracted revived interest. However, critical issues pertaining to the labile zinc anode and sluggish air cathode have yet to be adequately addressed. Here, we demonstrate a redox-mediated zinc-air fuel cell (RM-ZAFC) to tackle the above problems. Upon operation, the complex cobalt triisopropanolamine serves as an electrolyte-borne electron carrier and homogeneous catalyst to boost the 4e-oxygen reduction reaction in a separate gas diffusion tank, which makes the system free of a sophisticated air electrode. With mediation by the ultrafast reaction with a phenazine derivative, zinc could be liberated from the electrode to a separate "fuel" tank at high utilization (>90%), making it feasible to be "refueled" after it is depleted. Above all, RM-ZAFC has the combined advantages of both ZABs and alkaline fuel cells and can operate with high energy density, good flexibility, scalability and safety at low cost and thus is promising for various energy storage applications.