Highly conductive, hierarchical porous ultra-fine carbon fibers derived from polyacrylonitrile/polymethylmethacrylate/needle coke as binder-free electrodes for high-performance supercapacitors

Here, the treated ultra-fine needle coke particles (UNCs) are introduced in hierarchical porous ultra-fine carbon fibers by electrospinning and thermally treatment process of two immiscible polymers and UNCs precursor. The structure, morphology and electrochemical performance of the ultra-fine carbon fibers derived from polyacrylonitrile (PAN)/polymethylmethacrylate (PMMA)/UNCs are explored in detail. As a result, when the mass ratio of PAN to PMMA reaches 6: 4, the ultra-fine carbon fibers derived from PAN/PMMA/UNCs display a high surface area of 919.3 m2 g−1, a suitable mesoporous structure of meso/micro = 1.59. and exhibit a remarkable specific capacity (387.2 F g−1 at 0.5 A g−1) and excellent power performance. Furthermore, a comprehensive electrochemical performance of symmetrical supercapacitors was obtained: prominent energy density (27.87 Wh·kg−1 at 489 W kg−1) and ideal cyclic stability (97.5% capacity retention after 10,000 cycles at 1 A g−1). In addition, hierarchical porous ultra-fine carbon fibers derived from blend polymer and needle coke with high degree of graphitization, which provide a potential optional application for served as binder-free electrodes for electrochemical energy storage devices.