Preparation and performance of straw based activated carbon for supercapacitor in non-aqueous electrolytes

The activated carbon with honeycomb-like morphology for electrochemical double layer capacitors (EDLCs) was prepared from wheat straw by carbonization and subsequent activation with KOH. The product presented micro- and mesoporous structure with the peak pore size of 2.1 nm and high specific surface area of 2316 m2/g. The electrochemical capacitance performances of the activated carbon as EDLC electrodes were characterized by using cyclic voltammetry (CV), alternating current (AC) impedance. The specific capacitance of the activated carbon reached 251.1 F/g at 2 mV/s scan rate in the electrolyte of MeEt3NBF4/AN. The thermal gravimetric analysis of AN impregnated carbon was explored as a new approach to investigate the effectivity of pore for the electrolytes. The relationships between specific capacitance and scan rate, surface area and pore diameter were discussed.