电容特性的影响
(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 以煤焦油沥青为原料，在不同温度下调制得到碳质微晶结构的中间相沥青，采用化学活化法制得超级电容器用高比表面积活性炭。以制备的活性炭作电极材料组装模拟电容器，6 mol/L KOH溶液为电解液，考察了中间相沥青的调制温度对活性炭结构和电容行为的影响。结果表明：随着调制温度的提高，活性炭比表面积先增加后减小，在
关键字: 超级电容器；中间相沥青；活性炭；化学活化
on structure and electrochemical performance of activated carbons
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Using coal-tar pitch as raw material, the mesophase pitches with carbonaceous crystallites were produced at different temperatures, and the ultra-high surface area activated carbons for supercapacitors were prepared by chemical activation. Coin type cells using the prepared activated carbons as electrode materials were assembled, and 6 mol/L KOH solution was selected as the electrolyte. The effects of modification process of the mesophase pitches on the structures and the electrochemical behaviors of activated carbons were investigated. The results indicate that the specific surface area of activated carbons increases while then decreases with increasing temperature, and the surface area of activated carbon modificated at 450 ℃ is 3 250 m2/g. The micropore sizes are ranged from 1nm to 4 nm, and the unformed structure modificated at 350 ℃ is beneficial to pore-widening, so the activated carbons exhibits higher mesopore volume. When the temperature increases, the mesopore volume decreases. The capacitance of the activated carbon increases while then decreases with increasing temperature, and the maximum specific capacitance is 215 F/g, which is acquired from the carbon modificated at 450 ℃.
Key words: supercapacitor; mesophase pitch; activated carbon; chemical activation
