Enabling Stable Zn Anodes Through Solvation and Interphase Regulation by Dual‐Functional Organic Additives

The stability of Zn anode in aqueous Zn‐ion batteries (AZIBs) is severely compromised by dendrite growth, side reactions, and hydrogen evolution reactions (HER), resulting in poor cycling performance and low Coulombic efficiency (CE). Herein, a dual‐functional organic additive (DFOA) is introduced in the electrolyte to simultaneously modulate Zn2+ solvation and Zn‐electrolyte interphase for high‐performance AZIBs. Spectroscopic analysis and density functional theory calculations reveal that succinic anhydride (SA), as a representative DFOA, weakens Zn2+–H2O interactions and strengthens Zn2+–succinate anion coordination by partially replacing H2O molecules in Zn2+ solvation shell, thereby reducing desolvation energy and suppressing HER and corrosion. Succinate anions derived from DFOA preferentially adsorb onto the Zn surface and promote the formation of a stable solid–electrolyte interphase (SEI). As a result, Zn||Zn symmetric cells exhibit prolonged cycling stability exceeding 7100 h at 1 mAh cm−2, while Zn||Cu asymmetric cells maintain highly stable plating/stripping with an excellent CE of 99.7% over 6300 cycles. Furthermore, the Zn||NH4V4O10 (NVO) full cells with DFOA demonstrate 99.9% average CE (ACE) and retain 86% of their capacity after 3000 cycles. This work identifies an effective and practical DFOA strategy for stabilizing Zn anodes, offering a viable route toward high‐performance and long‐life aqueous Zn‐ion batteries.