Coordination and interface engineering to boost catalytic property of two-dimensional ZIFs for wearable Zn-air batteries

Metal organic frameworks (MOFs) have been considered as compelling precursor for miscellaneous applications. However, their unsatisfied electrocatalytic performance limits their direct application as electrocatalyst. Herein, by incorporating the cobalt-oxide bonds and polyaniline (PANI) with two-dimension zeolitic imidazolate frameworks (ZIFs), a novel bifunctional catalyst (Co-O-ZIF/PANI) for Zn-air battery was designed based on a facile and eco-friendly method. This Co-O-ZIF/PANI with optimized surface adsorption effect and suitable Co3+/Co2+ ratio, exhibits eminent electrocatalytic activity toward both oxygen reduction and evolution reaction. The as-assembled liquid ZABs based on Co-O-ZIF/PANI achieves a remarkable maximum power density of 123.1 mW cm−2 and low discharge-charge voltage gap of 0.81 V at 5 mA cm−2 for over 300 cycles. Operando Raman spectroscopy reveals that the excellent performance origins from the optimized surface chemisorption property of O2 and H2O brought by Co–O bonds and PANI. This work provides a novel prospect to develop efficient MOF derived bifunctional electrocatalysts by optimizing surface chemisorption properties.