Achieving Uniform Deposition of Zn with Amide Additives for Metal Anodes Stabilization

The practical applications of aqueous zinc-ion batteries (AZIBs) are hindered by detrimental effects such as dendrites formation at the Zn metal anode interface and parasitic side reactions induced by H₂O. Hence, we propose adding amide additives to the Zn sulfate electrolyte (ZSO) to regulate the composition and properties of the electrolytes, thereby stabilizing the Zn anode interface. Different amide molecules containing formamide (FA), acetamide (AA), or trifluoroacetamide (TFA) are discussed. The polar C═O group shared by amide molecules can interact with Zn²⁺, forming their solvation shells. The molecules can also facilitate the transport of Zn²⁺ and increase the conductivity of the electrolytes. Additionally, amide molecules can interact with H₂O through hydrogen bonds to limit the erosion of active H₂O on the Zn anode. The unique -H, −CH₃, and −CF₃ groups of the molecules result in different polarities and varying numbers of interaction sites with H₂O and Zn²⁺, leading to some differences in the protective effects of the Zn anode. The stability and lifespan of Zn||Zn batteries assembled with amide electrolytes have significantly improved, especially those with TFA. Moreover, the Zn||NH₄V₄O₁₀ full cells demonstrate remarkable capacity retention, and the overall performance of the batteries has also been enhanced.