Abstract: Using bamboo as raw material and KOH as activator, bamboo charcoal (BC) was prepared by KOH activation-microwave irradiation method.Effects of the activation time on properties of the products were investigated by means of XRD,SEM,cyclic voltammetry,galvanostatic charge/discharge,and electrochemical impedance spectroscopy.Results showed that KOH activation had no obvious effect on the crystalline structure of  BC particles,while it did influence on the particle′s surface morphology and electrochemical performance greatly.Mass specific capacitances of BC were 195,134,151,137 and 124 F/g at the activation time of 5,10,15,20 and 25 min,respectively.As prepared BC exhibited excellent capacitance and cycle stability when at the optimum activation time of 5 min.Under 500 mA/g,after 250 times charge/discharge the discharge specific capacitance of BC still reached 176 F/g and the capacity retention rate was over 90%.

Key words: bamboo charcoal, activation, specific capacitance, KOH, capacity retention rate