Green fabrication of hierarchically porous carbon microtubes from biomass waste via self-activation for high-energy-density supercapacitor

Abstract

Developing high-efficiency electrode materials is always desired for supercapacitor, in order to improve the energy density. Herein, we found that hierarchically porous carbon microtubes (HPCMTs) derived from plane tree fruit fluff via self-activation method demonstrated prominent supercapacitor performance as electrode materials, since they possessed hierarchical pore structure consisting of abundant micro- and mesopores, high specific surface area (SSA) and good wettability with electrolyte. The HPCMT-1100-6 with the largest SSA (2805 m2/g) and maximal total pore volume (1.98 cm3/g) was obtained at 1100 °C with dwelling time of 6 h. The HPCMT-1100-6-based cell in organic electrolyte showed an ultrahigh energy density of 46.3 Wh/kg at high power density of 1106 W/kg in 1.0 M TEABF4/AN, as well as splendid rate capability and impressive long-term cyclic stability. The energy density still can retain 35 Wh/kg even at an ultrahigh power density of 83.8 kW/kg, the capacitance retention maintains 96.4% after 10000 cycles at a current density of 10 A/g. This study provided a novel practical sustainable strategy for converting the abundant and low-cost biomass waste into high-valued porous carbons by the green self-activation method for high-energy-density supercapacitor.