Polyimide and polystyrene‐based activated carbon nanofibers with tubular structure for supercapacitor

Abstract

AbstractPolyimide (PI) and polystyrene (PS) blend electrospun fibers are prepared by electrospinning method. PI and PS are not completely compatible due to the difference of solubility and surface energy in electrospinning precursor, so PI/PS electrospun fibers have some phase separations along the electric field direction under the high‐voltage electrostatic force. PI with high carbon conversion served as carbon nanofibers, PS with low carbon conversion served as porogenic sacrificial agent, so PI/PS‐based activated carbon nanofibers derived from PI/PS electrospun fibers with well‐controlled opening tubular structure are obtained via thermally induced phase separation process. The morphology and electrochemical performance of activated carbon nanofibers are investigated by structural analysis and electrochemical measurements. The relationships among pores structure, electrolyte character and electrochemical performance of activated carbon fibers are extensively evaluated. Activated carbon nanofibers derived from PI/PS (mass ratio = 1:2) electrospun fibers with nano scale opening tube wall structure show a small charge transfer resistance and the short electric double layers forming time, but also suitable average pore diameter (3.74 nm), high BET specific surface area (952.5 m2 g−1) and average pore volume (0.532 cm3 g−1). Then, a comprehensive electrochemical performance can also be achieved in organic electrolyte: high energy density (31.80 Wh kg−1), good power density (3094.05 W kg−1) and low internal resistance (1.24 Ω). The findings reveal a guideline for the preparation of polymer‐based hierachical porous and opening tubular structure activated carbon nanofibers for electrochemical energy conversion and storage devices.