A percent-level amide additive for stable aqueous zinc-ion batteries

The Zn anode/electrolyte interface faces critical challenges, including hydrogen evolution reaction, corrosion, and dendrite growth that degrade battery performance. This study employs 1 mol% N-(2-hydroxyethyl) succinimide (NHS) as a multifunctional electrolyte additive to address these issues. The carbonyl groups (C=O) in NHS can strongly coordinate with Zn atoms and water molecules, selectively adhering to the Zn anode surface to displace H2O, thereby suppressing parasitic reactions while simultaneously reducing water activity in the electrolyte. The NHS can regulate Zn2+ solvation by replacing water molecules in the primary solvation sheath, thereby further facilitating Zn2+ desolvation by reducing the number of bound water molecules. Additionally, the NHS on the anode surface enables a homogeneous Zn2+ flux, resulting in uniform zinc deposition. As a result, the NHS enables a ZnZn symmetric cell to achieve 7,500 h cycling at 1 mA·cm−2, and a ZnCu cell to maintain 99.8% Coulombic efficiency over 3200 cycles. The ZnV2O5 full cell retains 82.5% capacity after 7,000 cycles. These findings highlight the proficiency of the NHS in securing Zn anodes for enhanced battery performance.