Eliminating electron localization by molecular array induces uniform zinc deposition enabling stable zinc anode

Electrolyte additives are considered as a straightforward and effective approach for steadying zinc anode. Nevertheless, most reported adsorption-type additives primarily focus on modulating the transport of Zn²⁺ and inhibiting side reactions, while neglecting the regulation of the surface state of zinc anode, which determines the final depositional behavior of Zn²⁺. Herein, vanillin acetate molecules incorporating strong electron-withdrawing and electron-donating groups, and conjugated benzene rings and capable of assembling into compact molecular array layers on zinc anodes are designed as functional electrolyte additives for optimizing the performance of zinc metal anode. The electron-donating group array towards the electrolyte facilitate the desolvation and transport kinetics of Zn²⁺, especially the electron-withdrawing group array close to zinc anode regulate the electron distribution on zinc anode to eliminate electron localization, which synergistically prompt the uniform deposition of Zn²⁺, thus achieving highly reversible zinc anode without dendrites. Consequently, the assembled Zn||Zn symmetrical batteries demonstrate prominent cycle life surpassing more than 2000 h and 800 h under 1 mA cm⁻²/1 mAh cm⁻² and 10 mA cm⁻²/3 mAh cm⁻², separately. Furthermore, the incorporation of this electrolyte additive enables NH₄V₄O₁₀||Zn full batteries with the high loading of 7.7 mg cm⁻² to exhibit an impressive capacity holding ratio of 87.43 % after 2000 cycles at 5 A/g. This research demonstrates the feasibility of stabilizing zinc anode by regulating the surface state of zinc anode through electrolyte additives, providing valuable insights for optimizing the electrochemical performance of zinc anodes.