Highly Compact Zinc Metal Anode and Wide‐Temperature Aqueous Electrolyte Enabled by Acetamide Additives for Deep Cycling Zn Batteries

Abstract Rechargeable aqueous zinc (Zn) batteries are a promising candidate for large‐scale energy storage, but the noncompact and dendritic Zn deposition, water‐induced parasitic reaction, and narrow operating temperature range severely hinder their practical application. Here, it is demonstrated that these challenges can be conquered by introducing low‐cost acetamide (Ace) into aqueous electrolytes. The non‐sacrificial Ace molecules with both donor and acceptor groups can disrupt the original H‐bonded network of water, replace the solvating‐H 2 O in Zn 2+ ‐solvation sheath, form dynamic adsorption on Zn, and create an H 2 O‐poor electrical double‐layer. Consequently, the presence of Ace suppresses water erosion on Zn, homogenizes Zn nucleation/growth, reduces water reactivity, and depresses the freezing point of electrolyte. The formulated Ace‐containing electrolyte features a wide temperature range from −20 to 60 °C and enables highly compact and dendrite‐free Zn electrodeposition even at 25 mAh cm −2 using a non‐pressure electrolytic cell. Moreover, the Ace‐containing electrolyte allows Zn electrodes to achieve a long‐term lifespan across −20–60 °C and excellent deep cycling stability under 85.3% depth‐of‐discharge (25 mAh cm −2 ) with over 400 h, and supports the stable operation of Zn–Iodine full batteries under harsh conditions.