Preparation of high performance supercapacitor materials by fast pyrolysis of corn gluten meal waste

Abstract

Fast pyrolysis of biomass wastes which is usually finished in a few seconds for the preparation of porous carbonaceous materials (PCMs) is much faster and more energy-efficient than the conventional hydrothermal carbonization (HTC) method and does not require the use of solvents. In this study, PCMs were prepared using corn gluten meal (CGM) waste by fast pyrolysis combined with chemical activation by KOH, and the capacitance performance of the resulting PCMs was investigated. The specific capacitance of PCM_P500 (fast pyrolysis at 500 °C) was 488 F g⁻¹ at a current density of 0.5 A g⁻¹, which is better than those of PCMs obtained at other pyrolytic temperatures (PCM_P300 and PCM_P400). Under the same conditions, the PCMs prepared by the HTC process exhibited relatively lower supercapacitance performance, i.e., PCM_H250 (HTC at 250 °C) is 433 F g⁻¹. The high performance of PCM_P500 was mainly attributed to the high specific surface area and pore structure, which depends on the thermal treatment methods. This work demonstrates that fast pyrolysis may be a promising technology for massive production of high performance PCMs from biomass wastes.