Preparation, Characteristics and Electrochemical Performance of Chinese Fir Bark-based Activated Carbon

Abstract

Fir bark-based activated carbon with high surface area and porosity was prepared from by a two-step method of low-temperature carbonization and KOH high-temperature activation using forestry waste fir bark as precursor, and applied as supercapacitor electrode materials. The central composite design(CCD) and response surface analysis were carried out using alkali carbon ratio and activation temperature as the experimental factors, and the mass specific capacitance at a current density of 0.5 A/g as the response value. The results showed that the specific surface area of fir bark-based activated carbon could reach 1 522 m2/g, and the maximum pore volume could reach 0.84 cm3/g. At the same time, the average pore size was 1.12 nm, and a large number of mesopores and micropores was coexisted. The interaction between the alkali carbon ratio and the activation temperature had significant impact on the capacitance. The optimal preparation process of Chinese fir bark activated carbon was obtained by response surface methodology: alkali carbon ratio of 3, and activation temperature of 605 ℃. The specific capacitance of the carbon material under this condition was 185.7 F/g. The electrochemical performance test of the activated carbon prepared under the optimized conditions indicated that the maximum specific capacitance could reach 188 F/g at 0.5 A/g, and it had a good rate capability(85.1%).