Highly Efficient and Stable Bifunctional Electrocatalyst with Alloy/Oxide Heterostructures for a Rechargeable Zinc-Air Battery

Constructing heterogeneous interfaces between transition metal alloys and oxides in a carbon-based composite catalyst is an effective strategy for boosting the oxygen evolution reaction and oxygen reduction reaction (OER and ORR). Inspired by this concept, a carbon-coated MnCoNi alloy/oxide catalyst (Ox-MnCoNi-C) was synthesized by carbonization of metal-organic frameworks (MOFs) and controllable reoxidation process. Owing to the synergetic interaction between abundant active sites on the heterogeneous interface and the good electron transfer rate of graphitic carbon, Ox-MnCoNi-C exhibits a low potential gap (Delta E) of 0.79 V. Meanwhile, the assembled liquid zinc-air batteries exhibit high power density (125 mW cm-2), superior primary discharge specific capacity (822 mAh gZn -1), and no less than 100 h of steady charging and discharging operation running at 5 mA cm-2. This approach will provide a generic template for the preparation and extension of MOF-derived carbon composite catalysts applied in oxygen electrocatalysis.