Preparation of high-performance activated carbons for electric double layer capacitors by KOH activation of mesophase pitches
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摘要: 以一种各向同性沥青为原料，通过不同恒温时间制备了具有不同软化点的两种中间相沥青，而后直接用KOH活化获得活性炭。考察了中间相沥青软化点对所得活性炭结构的影响，研究了以所制活性炭为电极材料的双电层电容器的性能。结果表明：两种中间相沥青的软化点分别为280℃和330℃，所得活性炭的比表面积分别为1337m2 · g-1和1300m2 · g-1。以两种活性炭为电极材料的双电层电容器在放电电流密度为50mA/g时的比容量分别为190.8F · g-1和255.6F · g-1。循环伏安测试表明：较低软化点中间相沥青制备的活性炭电极材料具有较好的矩形形状。Abstract: Two kinds of mesophase pitches with different softening points were prepared at different soaking times and directly activated with KOH to study the effects of the softening point on the textural characteristics of the resulting activated carbons and their behavior as electrodes in capacitors. Results show that the softening points of the two mesophase pitches are 280 and 330°C, and the specific surface areas of the activated carbons are 1337 and 1300m2 · g-1, respectively. The specific capacitance of the higher softening point mesophase pitch-derived carbon is higher (255.6F · g-1) than that of the lower softening point mesophase pitch-derived carbon (190.8F · g-1) at the same current density. Cyclic voltammograms show that the lower softening point mesophase pitchderived carbon exhibits better rectangular-shaped I-V curves. The softening points of the mesophase pitches prepared from even the same precursor can significantly affect the electrochemical performance of the resulting activated carbons.
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Key words:
- Capacitors /
- Activated carbons /
- Mesophase pitch /
- Electrochemical properties
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