Metal organic framework derived perovskite/spinel heterojunction as efficient bifunctional oxygen electrocatalyst for rechargeable and flexible Zn-air batteries.

Interface engineering strategy has been developed to design efficient catalysts for boosting electrocatalytic performance in past few decades. Herein, heterojunctions of PrCoO/CoO nanocages (PCO/CoO NCs) with atomic-level engineered interfaces and rich oxygen vacancies are proposed for Zn-air batteries. The synthesized product shows exceptional bifunctional activity and robust stability towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The enhanced catalytic capacity is primary attributed to the synergistic effect of PCO/CoO, evidenced by the experimental results and theoretical calculations. More importantly, the PCO/CoO NCs assembled liquid Zn-air battery exhibits a power density of 182 mW cm and a long-term operation of 185 h. When assembled into solid-state cable type battery, this newly designed catalyst also reaches a stable open circuit voltage (1.359 V) and a peak power density of 85 mW cm. Our findings provide essential guidelines of engineering heterostructured electrocatalysts for future wearable electronic devices.