Developing fast-charging Zn-air batteries is crucial for widening their application but remains challenging owing to the limitation of sluggish oxygen evolution reaction (OER) kinetics and insufficient active sites of electrocatalysts. To solve this issue, a reconstructed amorphous FeCoNiSx electrocatalyst with high density of efficient active sites, yielding low OER overpotentials of 202, 255, and 323 mV at 10, 100, and 500 mA cm-2 , respectively, is developed for fast-charging Zn-air batteries with low charging voltages at 100-400 mA cm-2 . Furthermore, the fabricated 3241.8 mAh (20 mA cm-2 , 25 °C) quasi-solid Zn-air battery shows long lifetime of 500 h at -10 and 25 °C as well as 150 h at 40 °C under charging 100 mA cm-2 . The detailed characterizations combine with density functional theory calculations indicate that the defect-rich crystalline/amorphous ternary metal (oxy)hydroxide forms by the reconstruction of amorphous multi-metallic sulfide, where the electron coupling effect among multi-active sites and migration of intermediate O* from Ni site to the Fe site breaks the scaling relationship to lead to a low theoretical OER overpotential of 170 mV, accounting for the outstanding fast-charging property. This work not only provides insights into designing advanced OER catalysts by the self-reconstruction of the pre-catalyst but also pioneers a pathway for practical fast-charging Zn-air batteries.
Keywords: Zn-air batteries; fast charging; multi-metallic sulfides; oxygen evolution reaction; reconstruction.
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