Rebuilding Hydrogen Bond Network and Adjusting pH by Electrolyte Additives for Stabilizing Zinc Anode

Aqueous zinc ion batteries (AZIBs) face challenges such as zinc dendrite growth, hydrogen evolution reaction, and side reactions, which limit their practical application. This study introduces sodium cocoyl isethionate (SCI), a surfactant rich in hydrogen-bond donors and acceptors, as a multifunctional electrolyte additive. By combining with free water, the hydrogen bond network in the electrolyte is rebuilt, promoting uniform Zn2+ deposition and suppressing byproduct formation, while simultaneously regulating the pH of the electrolyte and effectively resolving hydrogen evolution issues. Compared to ZnSO4 (ZSO) electrolyte, the Zn|ZSO-SCI|Zn symmetric cell using the ZSO-SCI electrolyte extended cyclic stability at 1 mAh cm–2 and 5 mA cm–2. Under conditions of 1 mAh cm–2 and 1 mA cm–2, the Zn|ZSO-SCI|Cu half-cell exhibited an average CE of 99.02% after 300 cycles, whereas the Zn|ZSO|Cu half-cell achieved an average CE of 95.91% after fewer than 50 cycles. In a Zn||AC capacitor configuration, the ZSO-SCI system maintains a capacity retention of 87.3% after 10,000 cycles, significantly outperforming its ZSO counterpart. This work not only extends battery cycle life via the SCI additive but also proposes a comprehensive strategy for zinc anode protection through hydrogen-bond network regulation, offering valuable insights for advancing AZIBs toward next-generation energy storage applications.