萃取温度对无灰煤结构及煤基活性炭电化学性能的影响

Effect of Extraction Temperature on Hyper-coal Structure and Electrochemistry of Coal-Based Activated Carbon

以内蒙古褐煤为原料,N-甲基吡咯烷酮为萃取剂,在不同温度下萃取制备无灰煤,进而利用KOH活化法制备活性炭,探究萃取温度对活性炭电化学性能的影响。结果表明,无灰煤萃取温度对煤基活性炭电化学性能有显著影响。对无灰煤及原料褐煤的灰分含量,表面官能团含量和对应活性炭的比表面积、孔结构及其电化学性能进行对比发现,330℃下萃取制备出的无灰煤在碱煤质量比3∶1,活化温度650℃,活化时间2h的活化过程中具备最适宜的反应性,对应活性炭比表面积高达1 252 m^2·g^(-1),表面官能团含量适中,在3 mol·L^(-1)KOH电解液中50 mA·g^(-1)电流密度下比电容高达322 F·g^(-1),2 A·g^(-1)的电流密度下比电容保持率仍可接近90%。

The Inner Mongolia lignite was used to prepare hyper-coal(HPC)at different temperatures by N-methylpyrolidone during KOH extraction.To explore the effect of extraction temperatures on activated carbons(ACs),the activation was operated at the same condition,mKOH∶mcoal=3∶1 and activated at 650℃for 2 hours.The results show that the extraction temperature of HPC has great effect on the electrochemical properties of HPC-based ACs.Comparing the ash contents,surface oxo-functional groups,the specific surface areas,pore structures and electrochemical performances of the corresponding ACs with the lignite,the HPC prepared at 330℃is in possession of the most suitable reactivity and its specific surface area of corresponding ACs could reach 1 252 m2·g^-1 with appropriate amount of surface oxo-function groups.Besides,the specific capacitor could still retain almost 90%in 3 mol·L^-1 KOH electrolyte at 50 mA·g^-1 reaching 322 F·g^-1,and a capacity retention as high as near 90%was achieved at 2 000 mA·g^-1.