【作者】 刘晶；

【导师】 秦学；

【作者基本信息】 天津大学 ， 无机化学， 2009， 硕士

【摘要】 超级电容器是一种介于电池和静电电容器之间的新型储能元件,与蓄电池相比具有较高的比功率,与静电电容器相比具有较大的比容量,而且运行温度范围宽、循环寿命长,具有广阔的应用前景,近年来成为研究的热点。目前,超级电容器的研究主要集中在高性能的电极材料的制备上。本文研究了几种MnO₂电极材料的制备方法,并制备了MnO₂和碳纳米管的复合材料,采用循环伏安（CV）、恒流充放电、交流阻抗测试（EIS）、X射线衍射（XRD）、扫描电子显微镜（SEM）以及透射电子显微镜（TEM）,对MnO₂电极的性能和形貌进行了测试和表征。本文的主要内容如下:以过硫酸铵为氧化剂,硫酸锰为还原剂,利用水热法,在不同的温度条件下合成纳米MnO₂,电化学测试表明反应温度为90℃时的产物具有最好的电容性,在2mA·cm^-2的放电电流密度下,电容值可达140F·g^-1。同样条件下,以高锰酸钾为氧化剂,硫酸锰为还原剂,合成纳米MnO₂,XRD测试表明反应产物皆为α-MnO₂,电化学测试表明,同样是90℃时的产物具有最高的电容值,为108F·g^-1。以硫酸锰为原料,使用电解法制备MnO₂,由实验结果可知,电容值随着硫酸浓度的提高和扫描速率的增大而增大,随着电解电压的升高而降低。电解法制备的产物电容值最大可达到502F·g^-1,且经过多次循环后仍表现出良好的电容性能。将不同管径的碳纳米管和二氧化锰复合,考察了碳纳米管的管径和碳纳米管的质量百分比对复合材料电化学性能的影响,测试结果表明,复合后二氧化锰比容量得到明显提高,碳管的质量百分比占到40%时,复合材料比例达到最佳,电容值达到238F·g^-1。更多还原

【Abstract】 Supercapacitors are new energy storage components between batteries and electrostatic capacitors, they have excellent properties, such as higher power density compared with rechargeable batteries, larger specific capacitor compared with conventional capacitors, and broad operating temperature range and long cycle life. Supercapacitors have become a hotspot in research because of their wide potential application.Studies on supercapaitors main focus on the preparation of high performance electrode materials now. In this dissertation we studied several methods for the preparation of manganese dioxide electrode material for supercapacitor, and prepared compound materials of manganese dioxide and carbon nanotubes. The capacitive property of manganese dioxide materials were investigated using cyclic voltammetric（CV）, constant current charge/discharge and electrochemical impedance spectrometry（EIS）. X-ray diffraction （XRD）, scanning electron microscope（SEM） and transmission electron microscope （TEM） were used to analyze the structure of MnO₂. The main results are as follows:Prepared MnO₂ by hydrothermal method in different temperatures, and took （NH4）2S2O8 as oxidant and MnSO4 as reductant, The experimental results show that the product made in 90℃has the best capacitance, at the current density of 2mA·cm^-2, the specific capacitance achieved 140F·g^-1. At the same conditions, took KMnO4 as oxidant and MnSO₄ as reductant, and synthesised MnO₂, the results of XRD indicate that the sample isα-MnO₂, and the experimental results show that the product made in 90℃also has the best capacitance, the specific capacitance is 108F·g^-1.Took MnSO4 as raw materials and prepared MnO₂ by electrolysis method, From the experimental results we can know that with the increase of concentration of H2SO4 and scan rate, the specific capacitance of MnO₂ electrode increased. The maximum specific capacitance of the product is 502F·g^-1 and it has good cycling performance.Composite compounds with carbon nanotubes of different diameter and manganese dioxide, the effert of the carbon nanotubes’diameter and the percentage of the carbon nanotubes on the specific capacitance of compounds were studied. The results show that after composite, the specific capacitance of manganese dioxide increased obviously, when the percentage of the carbon nanotubes achieved 40%, the best specific capacitance is 238F·g^-1.更多还原