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杉木树皮基活性炭的制备、表征及其电化学性能研究

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

  • 摘要: 以林业废弃物杉木树皮作原料,通过低温炭化和KOH高温活化两步法制备了具有高表面积和孔隙率的杉木树皮基活性炭并应用于超级电容器电极材料。以碱炭比和活化温度为试验因素,以电流密度0.5 A/g下的质量比电容为响应值,进行中心复合设计(CCD)和响应面分析。研究结果表明:杉木树皮基活性炭的比表面积最高可达1 522 m2/g,最大孔容可达0.84 cm3/g,此时平均孔径为1.12 nm,且同时存在大量的中孔和微孔。碱炭比和活化温度的交互作用对比电容的影响显著,响应面法优化得到杉木树皮基活性炭最佳制备工艺为:碱炭比值为3,活化温度605 ℃,此条件下炭材料的比电容为185.7 F/g。对优化条件下制备的活性炭进行电化学性能测试发现:在0.5 A/g条件下的最大比电容为188 F/g,且具有良好的倍率性能(85.1%)。

     

    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%).

     

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