Robust zinc anode modification layer with hydrophobic-cation selectivity for stabilized aqueous zinc ion batteries

Interfacial side reactions triggered by aqueous electrolytes and the growth of dendrites are urgent problems in the field of aqueous zinc ion batteries. This study introduces a novel modification layer for zinc anodes in aqueous zinc ion batteries (ZIBs). The layer, named PCL-Nafion@Zn (P-N@Zn), combines hydrophobic properties (from PCL) with cation selectivity (from Nafion). This combination effectively tackles common issues in ZIBs, such as dendrite growth and water-related side reactions. While Nafion as the filler is enriched with sulfonic acid groups, which promote the transport of zinc ions and facilitates the formation of smooth Zn deposition layer. Benefiting from the effective protection, the PCL-Nafion@Zn||Cu cell has a high Coulombic efficiency (99.3 %) at 2 mA cm−2, and the symmetric cell has a stable cycling of more than 2,900 h at 1 mA cm−2. Have a good cycling stability at high current densities. In addition, the full cell maintains a residual capacity of more than 90 mAh/g after 500 cycles at 1 A/g, which is superior to bare Zn and Nafion@Zn cells.