Triple-Functional Amorphous In2O3 Anode Protection Layer Design for High-Performance Aqueous Zinc Ion Batteries

Protective coatings for Zn anode are developed to suppress Zn dendrite growth, inhibit hydrogen evolution reaction (HER), and provide good anti-corrosion properties. However, preparing protective coatings with all three of these characteristics remains a challenge. In this study, a triple-functional amorphous In₂O₃ protective layer for Zn anodes is designed. The high redox potential of In/In³⁺ ensures the stability of the coating in aqueous electrolytes and effectively suppresses HER. Theoretical calculations indicate that the amorphous In₂O₃ protective layer has high Zn²⁺ affinity, which lowers the nucleation barrier for Zn²⁺ and suppresses dendrite growth. Furthermore, the anisotropy of this amorphous material provides homogeneous Zn²⁺ adsorption sites and enhances corrosion resistance. Consequently, amorphous In₂O₃@Zn symmetric batteries have excellent stability and a cycle life far exceeding that of bare Zn, showing the ability to undergo continuous stripping/plating at 1 mA cm⁻² for >5400 h. At a current density of 10 A g⁻¹, an amorphous In₂O₃@Zn//Ca-V₂O₅ full cell retains a specific capacity of 307.3 mA h g⁻¹ after 5000 cycles (cycle retention: 76%). The successful preparation of In₂O₃@Zn provides a new approach for obtaining highly stable and long-life Zn anodes.