Advanced PEI/PAN Membrane to Suppress Zinc Dendrite Growth in Zinc Metal Batteries

Aqueous zinc-ion batteries (AZIBs) are a potential new technology in energy storage due to their high energy density, affordability, and environmental friendliness. The development of AZIBs is still hampered by unchecked zinc dendrite formation during cycling, which results in an unstable interface, a short cycling life, and a considerable capacity decline with security issues. Herein, we demonstrate a novel nanofiber membrane based on polyetherimide-polyacrylonitrile (PEI/PAN) polymer via electrospinning method with entangled nanofibers for AZIBs applications. The as-fabricated PEI/PAN membrane has a homogeneous, tortuous, and linked porous structure, high porosity, and superior electrolyte wettability. The resulting PEI/PAN membrane exhibits a decent thermal stability of 200 °C and a strong ionic conductivity of up to 5.3×10^-4 S cm^-1. This membrane gives Zn/Zn symmetric cells an ultralong cycle life of more than 250 hours at 3 mA cm^-2. In the meantime, the MnO₂/Zn cell outperforms commercial filter paper regarding cycle stability and rate performance. This work demonstrates the design of a straightforward technique to fabricate advanced nanofiber membranes for AZIBs to modify Zn²⁺ deposition behavior and improve Zn dendrite resistance.