氧化-活化处理的超级电容器用高比电容活性炭
来源期刊：中南大学学报(自然科学版)2012年第12期
论文作者：朱晨 张远亮 刘洪涛
文章页码：4638 - 4645
关键词：超级电容器；活性炭；氧化－活化；比表面积；电容特征
Key words：supercapacitor; activated carbon; oxidation-activation; specific surface area; capacitive characteristics
摘 要：通过对普通颗粒活性炭采取不同优化工艺处理，发现经空气预氧化后，再用混合酸(磷酸+硫酸)或氢氧化钾进行活化处理，可得到高比电容超级电容器用活性炭。红外光谱和氮吸脱附分析表明：预氧化处理并没有明显增加其表面官能团，但有利于疏通孔道，提高活性炭的有效孔容积；混酸和强碱活化处理明显丰富活性炭的表面电活性基团，并且增大材料的比表面积。采用交流阻抗、循环伏安、恒流充放电等电化学方法对活化材料进行超级电容行为测试，表明经氧化-活化处理的活性炭电极传荷阻抗小、电容特征显著，循环性能稳定。在1.0 A/g电流条件下，经过空气氧化-混酸活化处理的活性炭(POAC_A)电极比容量为187 F/g，空气氧化－碱活化处理的活性炭(POAC_B)电极比容量达到206 F/g。
Abstract: Highly capacitance-enhanced activated carbons used for supercapacitors were obtained by treatment of low-cost granular activated carbons. The preferred technical process involves pre-oxidation and acidic or alkaline activation treatment. It is shown with the combination of IR spectra and N2 adsorption-desorption isotherms that the pre-oxidation treatment is beneficial to opening closed pores and raises the effective pore capacity, but has few effects on the increase of carbon surface functional groups. The mixed acid (3H3PO4+H2SO4) or alkali (KOH) treatment evidently fertilizes electroactive functional groups at the carbon surface. Meanwhile, the specific surface area of activated carbon is greatly increased. The capacitive behavior of the treated activated carbon is investigated by a.c. impedance, cyclic voltammetry, and galvanostatic charge-discharge measurements. The result shows that the pre-oxidation-activation treated activated carbon has low charge-transfer resistance, large electrochemical capacitance, and stable cycle life. Especially, the specific capacitance of the pre-oxidation-acidic activation treated activated activated carbon (POAC_A) and the pre-oxidation-alkaline activation treated activated activated carbon (POAC_B) at the charge-discharge current of 1.0 A/g reach 187 F/g and 206 F/g, respectively.
朱晨，张远亮，刘洪涛
(中南大学 化学化工学院 有色金属资源化学教育部重点实验室，湖南 长沙，410083)
摘 要：通过对普通颗粒活性炭采取不同优化工艺处理，发现经空气预氧化后，再用混合酸(磷酸+硫酸)或氢氧化钾进行活化处理，可得到高比电容超级电容器用活性炭。红外光谱和氮吸脱附分析表明：预氧化处理并没有明显增加其表面官能团，但有利于疏通孔道，提高活性炭的有效孔容积；混酸和强碱活化处理明显丰富活性炭的表面电活性基团，并且增大材料的比表面积。采用交流阻抗、循环伏安、恒流充放电等电化学方法对活化材料进行超级电容行为测试，表明经氧化-活化处理的活性炭电极传荷阻抗小、电容特征显著，循环性能稳定。在1.0 A/g电流条件下，经过空气氧化-混酸活化处理的活性炭(POAC_A)电极比容量为187 F/g，空气氧化－碱活化处理的活性炭(POAC_B)电极比容量达到206 F/g。
关键词：超级电容器；活性炭；氧化－活化；比表面积；电容特征
ZHU Chen, ZHANG Yuan-liang, LIU Hong-tao
(School of Chemistry and Chemical Engineering, Key Laboratory of Resource Chemistry of Nonferrous Metals,
Central South University, Changsha 410083, China)
Abstract:Highly capacitance-enhanced activated carbons used for supercapacitors were obtained by treatment of low-cost granular activated carbons. The preferred technical process involves pre-oxidation and acidic or alkaline activation treatment. It is shown with the combination of IR spectra and N2 adsorption-desorption isotherms that the pre-oxidation treatment is beneficial to opening closed pores and raises the effective pore capacity, but has few effects on the increase of carbon surface functional groups. The mixed acid (3H3PO4+H2SO4) or alkali (KOH) treatment evidently fertilizes electroactive functional groups at the carbon surface. Meanwhile, the specific surface area of activated carbon is greatly increased. The capacitive behavior of the treated activated carbon is investigated by a.c. impedance, cyclic voltammetry, and galvanostatic charge-discharge measurements. The result shows that the pre-oxidation-activation treated activated carbon has low charge-transfer resistance, large electrochemical capacitance, and stable cycle life. Especially, the specific capacitance of the pre-oxidation-acidic activation treated activated activated carbon (POAC_A) and the pre-oxidation-alkaline activation treated activated activated carbon (POAC_B) at the charge-discharge current of 1.0 A/g reach 187 F/g and 206 F/g, respectively.
Key words:supercapacitor; activated carbon; oxidation-activation; specific surface area; capacitive characteristics
