Built-in Electric\nField in 1D/2D Heterostructure Boosts\nZinc Air Battery Performance

The realization of a rechargeable zinc-air battery (ZAB)\nis hindered\nby the low intrinsic oxygen evolution reaction (OER) and oxygen reduction\nreaction (ORR) activities. In this work, an abundant built-in electric\nfield is noticed in a 1D/2D CoO/CoS<sub>2</sub> heterostructure, triggering\nelectron transfer from CoO to CoS<sub>2</sub> associated with a downshifted\nd band center of the Co atom mitigating the strong electrochemical\nadsorption of *OH species on active sites; thereby, boosted OER and\nORR performance are achieved. Namely, the OER specific activity of\nCoO/CoS<sub>2</sub> is enhanced by 3.8- and 2.2-fold compared to the\ncounterpart of CoO and CoS<sub>2</sub>, respectively. Furthermore,\nthe kinetic current density of CoO/CoS<sub>2</sub>, a fingerprint\nof intrinsic ORR activity, is promoted by 46 and 6.6 times relative\nto CoO and CoS<sub>2</sub>. The rechargeable ZAB performance attains\n215.6 mW cm<sup>–2</sup>, 1.6-times better than Pt/C-IrO<sub>2</sub>. Moreover, the superior performance remained for 600 h.\nBesides, the battery performance of the all-solid-state ZAB reaches\n83.8 mW cm<sup>–2</sup>, revealing its promising application\nin wearable device.