Preparation of <scp>GF</scp> / <scp>PFSA</scp> Hybrid Matrix Separators for High‐Stability Aqueous Zinc‐Ion Batteries

ABSTRACT Aqueous zinc‐ion batteries (AZIBs) are promising candidates for large‐scale energy storage owing to their safety and cost advantage. However, zinc dendrites and side reactions severely impact their cycling stability. This work fabricated a composite separator by doctor‐blade coating a perfluorosulfonic acid (PFSA) solution onto a glass fiber (GF) separator. SEM showed that a continuous smooth coating was formed, effectively covering most of the pores of the original GF. The modified separator showed enhanced hydrophobicity with a contact angle of 140.1°. Zn||Zn symmetric cells employing the GF/PFSA separator deliver a cycle life exceeding 1800 h at 0.5 mA cm −2 , corresponding to an approximately 30‐fold improvement over the pristine GF separator. The Zn 2+ transference number increases from 0.63 for GF to 0.83 for GF/PFSA, and the Zn||Cu cells maintain a Coulombic efficiency above 99% during prolonged cycling. The full cell constructed with Zn||V 2 O 5 exhibited a capacity retention of 71% after 1500 cycles at 1A·g −1 , while the original GF system retained only 4%. These results demonstrate that the GF/PFSA composite separator can effectively improve Zn plating/stripping reversibility and full‐cell stability, providing a practical separator design strategy for high‐performance aqueous zinc‐ion batteries.