Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE A hydrophobic composite separator consisting of perfluorosulfonic acid and glass fiber is fabricated for aqueous zinc-ion batteries. It enables stable Zn||Zn cycling for over 1800 h and maintains 71% capacity retention in Zn||V2O5 full cells after 1500 cycles, compared with 4% for pristine GF separator.

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 Zn2+ 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||V2O5 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.