Modulating Solvation Shell with Acrylamide Electrolyte Additives for Reversible Zn Anodes

The reconsideration of aqueous zinc-ion batteries (ZIBs) has been motivated by the attractive zinc metal, which stands out for its high theoretical capacity and cost efficiency. Nonetheless, detrimental side reactions triggered by the remarkable reactivity of H₂O molecules and rampant dendrite growth significantly compromise the stability of the zinc metal anode. Herein, a novel approach was proposed by leveraging the unique properties of acrylamide (AM) molecules to increase the driving force for nucleation and parasitic reactions. Combined with experimental data and theoretical simulations, it is demonstrated that the incorporation of AM additive can reconstruct the solvation shell around Zn²⁺ and reduce the number of active H₂O molecules, thereby effectively reducing the H₂O molecule decomposition. Consequently, the Zn//Zn symmetric batteries with AM-containing ZnSO₄ electrolytes can attain excellent long-term performances over 2000 h at 1 mA cm^-2 and nearly 500 h at 10 mA cm^-2. The Zn//VO₂ full batteries still display improved cycling performances and a high initial discharging capacity of 227 mA h g^-1 at 3 A g^-1 compared to the ZnSO₄ electrolyte. This electrolyte optimization strategy offers new insights for achieving long-term ZIBs and advances the progress of ZIBs in energy storage.