Green H2O2 activation of electrospun polyimide-based carbon nanofibers towards high-performance free-standing electrodes for supercapacitors

Abstract

Free-standing carbon nanofibrous membranes are prepared by carbonization and H 2 O 2 activation of electrospun polyimide nanofibrous membranes. The green and facile H 2 O 2 activation method not only regulates the pore structure of carbon nanofibers but also introduces rich oxygen species, rendering a hierarchically porous and heteroatom-doped carbon electrode for supercapacitors. The optimal electrode (PI800-8) shows a high specific capacitance of 339.9 F g −1 (0.5 A g −1 , 6 M KOH electrolyte) and excellent cycle durability with a capacitance retention of 98.4 % after 50,000 cycles (5 A g −1 ). Particularly, a non-aqueous symmetric supercapacitor assembled with 1 M Et 4 NBF 4 electrolyte shows a high operating voltage of 2.8 V, and delivers the maximum energy/power density of 37.3 Wh kg −1 and 28.0 kW kg −1 , respectively. The H 2 O 2 activation method provides a green, efficient, and versatile strategy to improve the pore properties and chemical compositions of porous carbon materials towards energy applications. • The N/O-codoped carbon nanofibrous membranes were prepared by carbonization/activation of commercial electrospun polyimide nanofibrous membranes. • The green and cost-effective H 2 O 2 activation was proposed to ameliorate the pore and chemical properties of carbon nanofibrous membranes. • Excellent comprehensive performance was presented for both aqueous/non-aqueous symmetric supercapacitor.