Weak‐Water‐Coordination Electrolyte to Stabilize Zinc Anode Interface for Aqueous Zinc Ion Batteries

The performance of zinc‐ion batteries is severely hindered by the uncontrolled growth of dendrites and the severe side reactions on the zinc anode interface. To address these challenges, a weak‐water‐coordination electrolyte is realized in a peptone‐ZnSO4‐based electrolyte to simultaneously regulate the solvation structure and the interfacial environment. The peptone molecules have stronger interaction with Zn2+ ions than with water molecules, making them more prone to coordinate with Zn2+ ions and then reducing the active water in the solvated sheath. Meantime, the peptone molecules selectively adsorb on the Zn metal surface, and then are reduced to form a stable solid‐electrolyte interface layer that can facilitate uniform and dense Zn deposition to inhabit the dendritic growth. Consequently, the Zn||Zn symmetric cell can exhibit exceptional cycling performance over 3200 h at 1.0 mA cm−2/1.0 mAh cm−2 in the peptone‐ZnSO4‐based electrolyte. Moreover, when coupled with a Na2V6O16·3H2O cathode, the cell exhibits a long lifespan of 3000 cycles and maintains a high capacity retention rate of 84.3% at 5.0 A g−1. This study presents an effective approach for enabling simultaneous regulation of the solvation structure and interfacial environment to design a highly reversible Zn anode. A weak‐water‐coordination electrolyte based on a peptone‐ZnSO4‐based electrolyte is designed to modulate the solvation structure of Zn2+ ions and interfacial environment. The peptone molecules can solvate with Zn2+ ions and eliminate the water molecules to decrease the water activity. Meanwhile, the peptone molecules selectively adsorb on the Zn metal surface, and then are reduced, forming a stable solid‐electrolyte interface layer to enable uniform and dense Zn deposition.