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1、摘 要摘 要碳纳米管(Carbon Nanotubes，CNTs)具有窄孔径分布、高比表面积利用率、高电导率和高稳定性,，被认为是为超级电容器电极材料的理想电极材料之一。而取向碳纳米管阵列(Carbon Nanotube Array，CNTA)由于 CNTs 的独特的排列方式更加适合在超级电容器中的应用。在本论文中，分别制备 CNTA 电极、MnO 2 电极、CNT/MnO2 复合电极和 CNTA/MnO2 复合电极，并在 0.5 mol/L Na2SO4 电解液中进行电化学特性测试和分析。通过一系列的实验，得到以下结论：1) 碳纳米管阵列电极在 0.63mA 电流下的比电容为 4.34mF/
2、cm2(大约 8.68F/g)，其等效串联电阻为 1.3。2) 二氧化锰电极在 0.63mA 电流密度下比电容为 984.4mF/cm2(或 82.0F/g)，其等效串联电阻分别为 83.5；其充放电曲线具有明显的近似三角形的对称性分布，表明电极反应的可逆性好。3) 加入碳纳米管的 MnO2 电极(CNT/MnO 2)的比电容高于 MnO2 电极，同时具有更小的内阻，说明 MnO2 电极中加入碳纳米管，会明显的降低 MnO2 电极的等效串联电阻。4) 二氧化锰沉积时间分别为 60min 和 120min 的 CNTA/MnO2 复合电极(CM-60 和 CM-120)在 1.25mA 下比电容
3、分别为 91.3F/g 和 67.8F/g，等效串联电阻分别为 12.5 和 20.9。因此，二氧化锰的沉积时间过长不利于制备高容量和低内阻的复合电极，同时还会影响二氧化锰和碳纳米管阵列的附着性。5) CNTA/MnO2 复合电极的比容量大于 MnO2 电极，同时具备较低内阻，说明采用碳纳米管与二氧化锰的复合材料作为超大容量电容器的电极，既可以改善MnO2 半导体的导电性能，又可以产生较大的法拉第准电容。关键词：超级电容器，碳纳米管阵列，二氧化锰，复合电极材料，电化学特性摘要IAbstractCarbon Nanotubes (CNTs) are regarded as an ideal el
4、ectrode material for supercapacitors, as a result of their narrow pore distribution, large specific surface area, excellent conductivity and high electrochemical stability. Compared with CNTs, Carbon Nanotube Arrays (CNTAs) are more suitable for application in supercapacitors, due to the unique arra
5、ngement of CNTs in CNTAs. In this dissertation, CNTA electrode, MnO2 electrode and CNT/MnO2 composite electrode, as well as CNTA/MnO2 composite electrode were fabricated, respectively, and their electrochemical properties were investigated in 0.5 mol/L Na2SO4 electrolyte . Through a series of experi
6、ments, the following conclusions were drawn：1) CNTA electrode provided specific capacitance of 4.34mF/cm2( 8.68F/g) at 0.63mA, with Equivalent Series Resistance(ESR) of 1.3.2) MnO2 electrode, with high ESR of 83.5, had specific capacitance of 984.4mF/cm2( 82.0F/g) at 0.63mA, and its charge and disch
7、arge curve illustrated an obvious symmetry of the approximately triangular distribution, presenting a good reversibility of the electrode reaction.3) Compared with MnO2 electrode, MnO2 electrode with CNT(CNT/MnO2 electrode) showed higher specific capacitance and lower ESR. Therefore, by adding CNT,
8、the ESR of MnO2 electrode was evidently reduced.4) CNTA/MnO2 electrodes with 60min and 120min deposition time of MnO2(labeled CM-60 and CM-120) had specific capacitance of 91.3F/g and 67.8F/g, and ESR of 12.5 and 20.9, respectively. As a consequence, extremely long deposition time went against the f
9、abrication of electrode with high specific capacitance and low ESR. In addition, it could critically influence the adhesion of CNTA and MnO2.5) CNTA/MnO2 composite electrode could provide higher specific capacitance and lower ESR than MnO2 electrode, indicating that CNTA/MnO2 compound material as an
10、 electrode material of supercapacitors not only improves the conductivity of MnO2, but also produces pseudo-capacitors with high capacitance. AbstractIIKey words: Supercapacitors, Carbon Nanotube Arrays, Manganese dioxide, Composite electrode, Electrochemical properties目 录第一章 引言 .11.1 超级电容器 .11.1.1 超级电容器的特点 .11.1.2 超级电容器的研究意义及发展概况 .31.2 基于碳纳米管阵列的电极材料研究现状和趋势 .31.2.1 定向碳纳米管阵列 .41.2.2 碳纳米管阵列与金属氧化物的复合 .41.2.3 研究趋势 .41.3 本论文的研究背景、工作内容及意义 .5第二章 超级电容器的结构和工作原理 .62.1 超级电容器的结构 .62.1.1 电极材料 .62.1.2 电解液 .72.1.3 集电极和隔膜 .82.1.4 超级电容器外壳 .82.2 超级电容器工作原理 .82.2.1 双电层电容器的工作原理 .92.2.2 法拉第准电容器的工作原理 .102.3 本章小结 .
