Selective Adsorption of MAPTAC Constructs Water‐Deficient Electric Double Layer for Enhanced Zinc Battery Performance

Abstract The practical application of aqueous zinc‐ion batteries (AZIBs) is hindered by interfacial instability, side reactions, and dendrite formation at the zinc anode. In this study, N,N,N‐trimethyl‐3‐(2‐methylallylamino)‐1‐chloropropylammonium (MAPTAC) as a novel electrolyte additive to optimize the electrode/electrolyte interface is introduced. MAPTA ⁺ selectively adsorbs onto the zinc surface, effectively replacing water molecules in the inner Helmholtz plane and reconstructing a water‐deficient electric double layer (EDL). This unique interfacial structure suppresses hydrogen evolution and corrosion reactions, increases the hydrogen evolution overpotential, and enhances the corrosion resistance of the zinc anode. Furthermore, MAPTA ⁺ modulates the diffusion and deposition behavior of Zn ²⁺ , inhibits dendrite growth, and promotes uniform zinc deposition along the (002) crystal plane. As a result, the Zn||Zn symmetric cell achieves an extended cycle life of up to 8600 h at 1 mA cm ⁻² , while the Zn||Cu half‐cell delivers a high average Coulombic efficiency of 99.81%. The Zn||NH ₄ V ₄ O ₁₀ full cell based on the MAPTAC electrolyte also exhibits superior cycling stability and rate performance. This work provides new insight into EDL engineering for zinc anodes and offers a promising strategy for the rational design of high‐performance AZIBs electrolytes.