Electrospun PEI/PAN membrane for advanced Zn ion hybrid supercapacitors

The development of Zn-ion hybrid supercapacitors (ZIHSCs) is hindered by the separators' characteristic flaws, which include low mechanical flexibility, inadequate heat stability, poor ion transport, and electrolyte wettability. Herein, a high-performance Polyacrylonitrile (PAN)/Polyetherimide (PEI) porous nanofibers membranes are designed and prepared via the electrospinning method, which exhibits superior porosity of 88 %, electrolyte uptake of 837 %, and ionic mobility. Benefiting from its physical properties, the PEI/PAN exhibits high ionic conductivity, which is higher than that of the PAN and Filter paper separator, confirmed by electrochemical experiments in the 2 M ZnSO₄ electrolyte. As a result, the assembled Zn/PEI-PAN/JAC supercapacitor offers specific capacitance (148.8 Fg⁻¹), energy densities (52.9 Wh kg⁻¹), and a power density of 1600 W kg⁻¹ at 2 A g⁻¹. Furthermore, the Zn/PEI-PAN/JAC cells show high rate performance and outstanding durability over time after 5000 cycles at 10 A g⁻¹. This work provides a new avenue to design versatile membranes for ZIHSCs with high performance and safety.