水蒸气活化制备超级电容器木质活性炭的研究

摘要

In order to prepare activated carbons for supercapacitor electrode with low price and good performance, traditional steam activation method was employed to prepare activated carbons from masson pine wood. The elemental analyzer and the nitrogen adsorption/desorption were employed to analyze the element contents and pore structure of the activated carbons. The electrochemical performance of the activated carbon electrodes was examined by the methods including cyclic voltammetry, galvanostatic charge-discharge cycles and electrochemical impedance spectroscopy using 1-ethyl-3-methyl imidazole tetrafluoroborate/acetonitrile (EMIMBF4/AN) as electrolytes. The effects of activation temperature and time on the electrochemical performance of activated carbon were investigated. The results showed that the specific copacitance of activated carbon increased first and then decreased with the increment of activation temperature and activation time. The activated carbon prepared at carbonization temperature 900 ℃ and activation temperature 900 ℃ for 1 h reached the maximum of the specific capacitance. Its specific capacitance reached 155 F/g with a sweep speed of 5 mV/s and remaind 105 F/g at 100 mV/s,and the energy density in organic electrolyte was as high as 33.6(W·h)/kg.After 5 000 cycles,specific capacitance was remain at value of 89 %.%为了制备价格低廉、性能优良的超级电容器活性炭,以马尾松为原料,采用常规的水蒸气活化法制备了超级电容器木质活性炭.采用元素分析,N2吸附/脱附等手段分析了活性炭的元素含量和孔隙结构;采用循环伏安、恒电流充放电和交流阻抗等方法,分析了活性炭电极在以1-乙基-3-甲基咪唑四氟硼酸盐/乙腈为电解质溶液的超级电容器中的电化学性能,考察了活化温度、活化时间对木质活性炭电化学性能的影响规律.结果表明:随着活化温度的升高,活性炭的比电容量先增后降;随着活化时间的延长,活性炭的比电容量也呈现先增后降的变化趋势.在炭化温度900℃、活化温度900℃和活化时间1h的条件下制得的活性炭比表面积高达1647m2/g,总孔容积1.00cm3/g;在5mV/s的扫描速率下活性炭电极的比电容量最高,达到155F/g,且倍率性能和循环稳定性良好,循环5000次后比电容量保持率89%;其在有机电解液中的能量密度高达33.6(W·h)/kg.