Dipole-induced built-in electric field manipulation for regulating Zn electrodeposition topology in high-performance aqueous Zn ion storage

Aqueous Zn-ion storage offers high capacity and safety, but practical use is hindered by dendrite formation, side reactions, and hydrogen evolution, affecting stability and efficiency. Herein, tetramethylol acetylenediurea (TA) is proposed as an effective electrolyte additive that modulates the Zn²⁺ deposition environment via coordination competition. The polar functional groups of TA restructure the solvation sheath, while its molecular dipoles generate localized electric fields that accelerate Zn²⁺ migration and promote directional (002)-oriented deposition. These effects collectively suppress side reactions and enhance Zn plating/stripping reversibility. The four hydroxyl (–OH) and conjugated ketone groups (C=O) in the TA molecule have strong coordination ability (Lewis basicity) and can form a stable [Zn(TA)(H₂O)_n]²⁺ with Zn²⁺, reducing the number of free water molecules and the proportion of active water in the solvation sheath. The TA molecules are adsorbed onto the Zn anode surface, leading to the redistribution of the local spatial electric field and homogenization of ion flux dynamics. Its conjugated planar structure can induce Zn²⁺ to preferentially deposit along the (002) crystal plane. Zn//Zn symmetric cell using TA-containing ZnSO₄ electrolyte exhibits stable cycling for more than 2240 h at 1 mA cm⁻², 1 mAh cm⁻². The Zn//activated carbon (AC) full-cell can stably cycle 30,000 cycles at 5 A g⁻¹ with a capacity retention rate of 90 %. This study provides important insights into electrolyte engineering strategies for stabilizing Zn anodes, highlighting the potential of molecular design additives in next-generation Zn²⁺ energy storage systems.