超级电容器用沥青焦基活性炭的制备及其电化学性能
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摘要: 采用沥青焦为原料，制备了系列高比表面积活性炭作为超级电容器电极材料。用直流循环充放电、循环伏安及交流阻抗等表征方法比较了沥青焦基超级活性炭和日本可乐丽公司YP15活性炭的电化学性能。实验结果表明在KOH、H2SO4、(C2H5)4NBF4/碳酸丙烯酯(Propylene carbonate PC)及(C2H5)4NBF4/乙腈（Acetonitrile）体系中，沥青焦基活性炭的比电容随比表面积增加，其最高值分别为257F/g、228F/g、140F/g、142F/g，均超过了日本活性炭。沥青焦基活性炭电极在KOH体系中的等效串联电阻的体积电阻率与日本炭相差不大；在H2SO4体系中的电阻率均小于日本活性炭；在碳酸丙烯酯体系中的电阻率均大于日本活性炭；在乙腈体系中，活化剂 KOH与沥青焦比例为4 ：1、经800℃活化3h制备的活性炭的电阻率小于日本活性炭。Abstract: A series of petroleum coke-based superactivated carbons (SACs) was prepared by KOH activation. Electrochemical performance of the SACs and a porous carbon called YP15 (Kuraray Chemical Co., Japan) as electrodes of supercapacitors in aqueous and nonaqueous electrolytes were characterized and compared by chronopotentiograms, cyclic voltammetry and AC impedance spectrum analysis. It was found that the specific capacitances of SACs increased with surface area and the highest values in the electrolytes of KOH, H2SO4,(C2H5)4NBF4/propylene carbonate(PC), and (C2H5)4NBF4/acetonitrile, were 257F/g, 228F/g, 140F/g and 142F/g respectively, all greater than that of YP15. The ESR volume resistivities of the SACs were lower than that of YP15 in 1mol/L H2SO4, higher than that of YP15 in 1mol/L (C2H5)4NBF4/PC, and close to that of YP15 in 3mol/L KOH. The ESR volume resistivity of the SACs in 1mol/L (C2H5)4NBF4/acetonitrile, which was prepared at 800℃ for 3h using a KOH to petroleum coke ratio of 4∶1, was lower than that of YP15.
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Key words:
- Supercapacitors /
- Cyclic voltammetry /
- AC impedance /
- Activated carbons
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