Nanofiber‐Reinforced Composite Gel Enabling High Ionic Conductivity and Ultralong Cycle Life for Zn Ion Batteries

Abstract Despite the impressive merits of gel electrolytes for aqueous Zn‐ion batteries, it remains a significant challenge to design and develop the gel electrolyte with high ionic conductivity, excellent dimensional stability, and long cycle life. Herein, a composite electrolyte (PTP) with thermolastic polyurethane ‐poly(m‐phenylene isophthalamide) nanofiber‐reinforced polyvinyl alcohol gel strategy is proposed for highly reversible Zn plating/stripping. Mechanically robust and ultrathin PTP contains functional groups for building ion migration channels and immobilizing water molecules, which accelerates Zn 2+ migration and mitigates water‐related side reactions. Thus, the Zn anodes exhibit excellent electrochemical performance involving high cycling stability (6500 h at 5 mA cm −2 , 5 mA h cm −2 ) and achieving an exceptional cumulative capacity of more than 16 000 mA h cm −2 . This enhancement is well maintained when combined with MnO 2 cathode. This work provides a reasonable solution for stabilizing Zn anodes and also provides new ideas for the modification of nanofiber‐reinforced gel electrolytes.