Four-functional iron/copper sulfide heterostructure for alkaline hybrid zinc batteries and water splitting

Developing the tri-functional catalysts to facilitate the oxygen evolution, oxygen reduction and hydrogen evo-lution reactions (OER, ORR and HER) is meaningful for zinc-air batteries (ZABs) and water splitting. Herein, we construct a novel metal sulfide heterostructure (INF-FeCuS) composed of Cu7S4 and Fe0.95S1.05. INF-FeCuS ex-hibits the superior tri-functional catalytic property with the OER, ORR and HER potentials of 1.45 V at 100 mA cm-2, 0.68 V at 10 mA cm-2, 292 mV at 100 mA cm-2 respectively. INF-FeCuS with a high ion conversion ability also can be used in the alkaline zinc battery with a discharge specific capacity of 446.0 mAh/g. Using the four -functional INF-FeCuS, we can fabricate a new-type of alkaline hybrid zinc battery (AHZB) with a peak power density of 203.4 mW cm-2 and energy efficiency of over 70 %. Interestingly, a single AHZB with INF-FeCuS can drive the electrolyzer with INF-FeCuS to produce hydrogen.