Effect of the gradient constant temperature on the electrochemical capacitance of cotton stalk-based activated carbon

The cost-effective activated carbon based from waste cotton stalks by the KOH activation method is investigated as the electrode material in supercapacitor for the first time. Activation temperature control is one of the most important factors affecting the surface area and pore structure of activated carbon, and it influences the capacitive performance of activated carbon based from cotton stalk. The optimized conditions are as follows: cotton stalk base charcoals and activating agent with a mass ration of 1:4, at an activation temperature of 600, 700, and 800A degrees C for 1, 1, and 2 h, respectively. With these experimental conditions, the activated carbon presents excellent electrochemical characteristics. The specific capacitance of the prepared activated carbon was as high as 180 F g(-1)at 2 A g(-1) in 1.0 mol center dot L-1 Et4NBF4/AN electrolyte and the specific capacitance without obvious attenuation after 2000 cycles. So, it is reasonable to believe that the activated carbons from cotton stalks by the KOH gradient constant temperature activation method might be one of the innovative carbon electrode materials for supercapacitor.