超级电容器用高比表面活性炭的制备与电化学表征

Preparation and electrochemical characterization of an activated carbon material of high specific surface area for supercapacitor

以富含多环芳香烃的廉价有机物为前驱体，采用化学活化方法制备了超级电容器用高比表面活性炭和活性炭电极．考察了活化温度对活性炭电极比电容量的影响，研究了活性炭材料的比表面积和孔结构与活性炭电极的充放电性能之间的关系，并对活性碳电极进行了电化学表征．结果表明，在500-700℃范围内，随着活化温度的提高，活性炭电极的比电容量显著增大，当活化温度超过700℃时，活性炭电极材料的比电容量变化不明显．700℃活化温度下所制备的活性炭材料呈现明显的多孔结构，孔容为1．038cm^3／g，比表面积为1959m^3／g；所制成的活性炭电极比电容量为210F／g，等效内阻为0．9Ω．／cm^2，10mA／cm^2充放电500次后保持90％以上电容量，交流阻抗图谱在频率低于转化点时表现出纯粹的电容行为，循环伏安曲线显示出良好的可逆特性．

A low- cost organic compound comprising mainly polyarylate was selected as precursor and a chemical activation method was used to prepare an activated carbon material of large surface area, with which the activated carbon electrodes of high specific capacitance were fabricated for supercapacitor. The effect of activating temperature on the specific capacitance of activated carbon electrode was studied. The relationship between the pore structure, surface area and specific capacitance of activated carbon electrode were discussed. The electrochemical characterization was also conducted with cyclic vohammetry and AC impedance methods. The results showed that, in the range of 500 ℃to 700 ℃, the specific capacitance of activated carbon electrodes obviously increased with the increase of activation temperature. When the activation temperature is above 700 ℃, the specific capacitance of activated carbon changes little with further increase of activation temperature. The activated carbon prepared at 700 ℃ had obvious porous structure, and its pore volume and surface area were 1. 038 cm^3/g and 1 959 m^2/g, respectively. The electrode fabricated with the activated carbon prepared at 700 ℃ exhibited a high specific capacitance of 211 F/g at a charge- discharge current of 10 mA/cm^2, an ESR （equivalent series resistance ） of about 0. 9 Ω/cm^2, a residual capacitance more than 90% after 500 cycles. A pure capacitance behavior can be found at the frequency below the knee in its AC impedance spectroscopy. Its cyclic voltammetry curve shows good reversibility.