Hierarchical porous carbon nanofibers as binder-free electrode for high-performance supercapacitor

1D hierarchical porous carbon nanofibers (HPCNFs) are prepared via electrospinning ternary PAN/N,N'-dimethylformamide (DMF)/tetrahydrofurar (THF) and using commercially available nano-CaCO3 as template. In the process of carbonization, nano-CaCO3 template decomposes and releases CO2 to form micropores and mesopores. Macropores are generated by removing the CaO nanoparticles using acid subsequently. The hierarchical pores are fairly well distributed because the nano-CaCO3 particles are highly dispersed in the fiber due to the better wettability in binary solvent. The obtained HPCNFs attain high specific surface area without physical and chemical activation. The HPCNF mats, possessing freestanding architecture, are used as binder-free electrodes for supercapacitor. Because of high specific surface area, rational pore diameter distribution and binder-free characterization of electrodes, the HPCNFs display a high capacitance of 251 F g (1) at a current density of 0.5 A g (1) as well as excellent rate capability and outstanding cycling stability (over 88% capacitance retention after 5000 cycles at the current density of 1 A g (1)). These results demonstrate that the binary solvent method is effective to achieve high-performance electrode materials and it has a promising prospect on applications of energy storages. (C) 2016 Elsevier Ltd. All rights reserved.