Highly Reversible Zn Anode by Ion Flux Regulation and Micro-Corrosion Zone Division

Abstract

Aqueous Zn-ion batteries (AZIBs) are receiving continuous attention as candidates for the next generation batteries, but the poor reversibility of the Zn anode limits their further development. In recent years, researchers are obsessed with modifying the surface of the Zn anode and adjusting the solvation structure of Zn²⁺ to address these challenges. Here, we propose a novel strategy to improve the reversibility of the Zn anode by simultaneously regulating the Zn ion flux and dividing micro-corrosion zones on the Zn anode surface, thereby manipulating the deposition behavior of Zn²⁺ and relieving the corrosion of the Zn anode. This approach exploits the keto-enol tautomerism of α-acetyl-γ-butyrolactone (ABL) to develop a specifically designed additive: Zn²⁺ coordinated α-acetyl-γ-butyrolactone complex (ZnABL). With this innovative additive, the Zn anodes show excellent reversibility: Zn||Zn symmetric cell achieves a long cycle life of 7780 h (≈11 months). Furthermore, the Zn||Zn<inf>0.25</inf>V<inf>2</inf>O<inf>5</inf>·H<inf>2</inf>O near-ampere-hour pouch cell, featuring a high areal capacity of 7.9 mAh cm⁻², achieved an energy density of 106.17 Wh L⁻¹ and sustained more than 350 cycles. The success of ZnABL in modulating the Zn ion flux and compartmentalizing the micro-corrosion zone provides a novel option for the reversibility improvement of Zn anodes.