A corrosion-resistant zinc-chromium alloy layer for highly reversible aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are promising energy storage systems because of their inherent safety and excellent sustainability. In this study, a zinc-chromium alloy layer is electrochemically deposited on the Zn anode (ZnCr@Zn) to enhance its performance in aqueous electrolytes. The ZnCr alloy layer can effectively modulate and homogenize Zn²⁺ flux, thus significantly promoting uniform Zn deposition. Meanwhile, the corrosion-resistant ZnCr alloy layer protects Zn from detrimental side reactions, improving Zn plating/stripping reversibility. Consequently, the ZnCr@Zn anode achieves a high average Coulombic efficiency of 99.9% at 2 mA/cm² over 600 cycles. Furthermore, the ZnCr@Zn∥NH₄V₄O₁₀ coin cell reliably operates for over 2000 cycles at 2 A/g with a capacity retention rate of 88.7%. The ZnCr@Zn∥NH₄V₄O₁₀ pouch cell also demonstrates excellent stability over 160 cycles at a current density of 0.5 A/g. This work provides a facile approach to improve the Zn anode for high-performance AZIBs.