Konjac gel porous activated carbon (AC) has been prepared unprecedentedly using konjac as a natural carbon source via KOH for application in supercapacitors. The morphology and structure of the carbon materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectra (XPS). The unique porous structure and oxygen-enriched functional groups of the obtained material was beneficial for improving the capacitive performance; a high specific capacitance of 273.8 F g (1) with a current density of 1 Ag (1) and preferable stability over 5000 cycles (with a loss rate of only 3.7%) was exhibited in a 1 M KOH electrolyte solution. This work provides a new environmental-friendly, low cost, easy-to-use carbon source and also explores an economic and technologically novel strategy for carbon supercapacitors in applications relevant to environmental improvement. (C) 2018 Elsevier B.V. All rights reserved.