Boosted electrochemical properties of polyimide-based carbon nanofibers containing micro/mesopore for high-performance supercapacitors by thermal rearrangement

Abstract

In this work, the hydroxyl-containing polyimide(HPI) nanofibers were fabricated by the electrospinning of poly(amic acid)(PAA) derived from pyromellitic anhydride(PMDA) and 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(6FAP), followed by thermal imidization. After further thermal rearrangement from HPI to polybenzoxazole(PBO) and pyrolysis, the HPI-based carbon nanofibers(HPICNFs) were obtained with abundant nitrogen and oxygen doping content. The effects of PAA concentration, thermally rearranged time and carbonizing temperature on the electrochemical performance of HPICNFs were evaluated. When the PAA concentration was 20%, the thermal rearrangement time was 2 h and the carbonization temperature was 800 °C, the specific surface area and pore volume of the HPICNFs reached 1107.6 m2 g−1 and 0.6204 cm3 g−1. Due to the abundant micro- and mesoporous structures, the HPICNFs exhibited a high specific capacitance of 263.9 F g−1 and excellent capacity retention rate about 75% from 0.5 to 10 A g−1. After 10,000 charging and discharging cycles, the capacitance retention of the symmetrical coin cell was maintained at about 99.82%, indicating superior long-term charging-discharging cycle stability. Additionally, a light-emitting diode was successfully lighted up by the three coin cells. Thus, this work provides a facile way to prepare the HPICNFs by thermal rearrangement and carbonization, which are expected to be used as high-performance electrode materials for supercapacitors.