Desired spontaneous corrosion via a highly hydrophilic porous layer for aqueous zinc-ion batteries

Abstract

The high safety and environmental friendliness of aqueous zinc-ion batteries (AZIBs) provide high value in future grid-level energy storage applications. However, localized Zn dendrites and continuous side reactions of the Zn anode severely limit its reversibility and practical lifespan. In this study, we propose an approach for a stable zinc anode based on a highly hydrophilic porous zinc layer, which guides the in-situ formation of uniformly distributed zinc hydroxide sulfate (ZHS) via unavoidable corrosion in the electrolyte. The uniformly formatted ZHS layer endows superior corrosion resistance and a homogeneous electric field, resulting in a more uniform zinc ion flux. As a result, the growth of zinc dendrites and the subsequent generation of by-product ZHS were effectively suppressed, and the lifetime in the Zn||Zn symmetric batteries was significantly improved. With the optimized sputtering oblique angle of 45°, the Zn-45 symmetric batteries with highly hydrophilic surfaces show an ultra-long lifespan of over 3300 h at 0.5 mA cm-2 (22 times that of bare-Zn) and more than 1680 h at 1 mA cm-2 (170 h for bare-Zn). When paired with an α-MnO2 cathode, the assembled Zn-45||MnO2 full battery delivers good cycling stability over 1000 cycles (72.2%, 61.3% for bare-Zn) and better rate performance. This transformational strategy provides a unique perspective on the design of stabilized zinc anodes for high-performance AZIB.