General Oxygen Vacancy Engineering by Molten Zinc to Regulate Anode Redox for Durable Aqueous Zinc-Iodine Batteries.

Wang, Chao; Wang, Haobo; Ma, Xinxi; Guo, Taolian; Zheng, Anyu; Zhao, Yu; Li, Xiaoge; Wu, Yutong et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

Oxygen vacancy engineering plays a crucial role in regulating surface chemistry for managing redox behaviors. However, controllable implantation of oxygen vacancy and safe and cost-effective production remain challenging. Herein, we report a general molten zinc reduction technology to prepare oxygen-deficient oxides with tunable vacancy content, synthetic universality, and industrial compatibility under mildly elevated temperature. Taking TiO<sub>2</sub> as an example, theoretical study demonstrates thermodynamically favorable zinc affinity on TiO<sub>2</sub> with increasing surface coverage supporting molten Zn supply. Featuring favorable electronic structures and inferior hydrogen evolution activity, TiO<sub>2-<i>x</i></sub> nanoparticles were used to decorate aqueous Zn anodes, which demonstrate much improved cycling stability, verified by theoretical and <i>in situ</i> and <i>ex situ</i> investigations. Eventually, zinc-iodine batteries were assembled using modified Zn anodes, which achieved favorable cycling performance due to the regulated anode redox and alleviated self-discharge behaviors. This work provides a general oxygen vacancy engineering technology with an in-depth understanding for durable aqueous zinc batteries and related systems.