Ultra‐Stable Zn Anode Enabled by Fiber‐Directed Ion Migration Using Mass‐Producible Separator

Abstract Aqueous zinc‐ion battery (AZB) is a promising candidate for next‐generation energy storage owing to inherent safety and low cost. However, AZBs are currently plagued by Zn dendrite growth and undesirable side‐reactions, leading to poor cycling stability and premature failure. To restrain the uncontrollable Zn growth, a unique separator is developed based on polyacrylonitrile/graphene oxide (abbreviated as PG) composite nanofibers, which contain abundance of zincophilicity functional groups to regulate the migration and distribution of Zn 2+ ions in the separator. It is demonstrated that the cyano ligands on PG not only facilitate the dehydration of solvated Zn 2+ ions prior to deposition, but also form fast lanes to enable homogenous scattering of deposition spots. Benefiting from these features, the PG separator offers a high ionic conductivity of 7.69 mS cm ‐1 and a transference number of 0.74 for Zn 2+ . The Zn||Zn symmetrical cells with PG separators achieve an ultra‐stable cycle life over 13 000 h. Zn||Zn 0.27 V 2 O 5 full batteries with PG separators retain 71.5% of the original capacity after 2800 cycles at a high current density of 2 A g ‐1 . This study offers future research directions toward the design of multifunctional separators to overcome the limits of Zn metal anode in AZBs.