Effects of the molecular structure from pitch fractions on the properties of pitch-based electrospun nanofibers

Mesophase pitch was separated into different pitch fractions to investigate the effect of pitch fractions on the properties of their nanofibers prepared by electrospinning. The evolution of different pitch fractions-derived nanofibers during stabilization and carbonization were explored, and the properties of the resultant carbon nanofibers (CNFs) as electrode materials for supercapacitor were compared. Results indicated that the hexane insoluble-toluene soluble (HI-TS) and toluene insoluble-tetrahydrofuran (THF) soluble (TI-THFS) fractions had good spinnability due to their narrow molecular weight distribution. Moreover, compared with HI-TS and THF insoluble (THFI), TI-THFS consisted of appropriate aromaticity and branched alkyl groups which promoted the stabilization and carbonization behaviors of its nanofibers, resulting in maintaining ideal fiber morphology of TI-THFS-derived nanofiber due to the mitigation of their exothermic reactions. Meanwhile, the TI-THFS-derived CNFs presented the highest surface area of 543 m(2) g(-1) and exhibited an excellent specific capacitance of 167 F g(-1) at 0.5 A g(-1) in 6 M KOH electrolyte.