Modulation of Zn2+ Solvation Structure and Deposition Behavior to Achieve High-Performance Zn Anodes

Abstract

Aqueous zinc-ion batteries (AZIBs) have gained wide attention as a promising next-generation energy storage solution, owing to their inherent safety, eco-friendliness, and exceptional volumetric capacity (5855 mAh cm^–3). However, the severe dendrite formation and side reactions of the Zn anode have impeded the development of AZIBs. Herein, a low-cost, easy-to-handle, and efficient small-molecule electrolyte additive, 1-Methoxy-2-propanol (PM), is employed to address these issues. The multifunctional additive can inhibit side reactions by disrupting the electrolyte’s hydrogen-bonding network and adjusting the solvated structure of Zn²⁺. Additionally, it can induce the preferential orientation deposition of Zn(002) on the surface of the Zn anode. It is worth mentioning that the PM-modified electrolyte enables the Zn||Zn symmetric cell to achieve an ultralong cycling stability of 2400 h (1 mA cm^–2, 1 mAh cm^–2) and 3000 h (5 mA cm^–2, 1 mAh cm^–2), while the Zn||Cu asymmetric cell maintains a high average Coulombic efficiency of 99.49% over 650 cycles (5 mA cm^–2, 1 mAh cm^–2). In addition, compared to the ZnSO₄ electrolyte, the full cell using the PM modified electrolyte exhibits higher capacity retention. This study provides a strategic approach to designing multifunctional electrolyte additives for high-performance AZIBs.