Engineering Cost-Efficient CoS-Based Electrocatalysts for Rechargeable Zn-Air Battery Application

The development of low-cost and efficient electrocatalysts toward the oxygen evolution reaction (OER) is crucial for clean energy devices such as metal-air batteries and fuel cells. Herein, a novel CoS@FeOOH electrocatalyst is synthesized by in-situ deposition of FeOOH nanoparticles on metallic organic frame (MOF) derived CoS hollow polyhedrons. Due to the coupling synergetic effect of FeOOH and CoS, CoS@FeOOH presents an excellent OER catalytic performance with both high electrocatalytic activity and durable cycling stability, far superior to the pristine CoS and commercial RuO2 electrocatalysts. The assembled rechargeable zinc-air battery (ZAB) using CoS@FeOOH as the OER electrocatalyst shows a maximum power density of 89.1 mW cm-2 and continuously runs 60 h without evident polarization increment, which is far better than the ZAB using the commercial RuO2 OER electrocatalyst. The robust catalytic performance of the CoS@FeOOH electrocatalyst is mainly attributed to the regulated electronic configurations accelerating charge transfer, abundant oxygen vacancies promoting catalytic activity, and an FeOOH protection layer inhibiting active Co dissolution.