【作者】 余能飞；

【导师】 高立军；

【作者基本信息】 南昌大学 ， 物理化学， 2008， 硕士

【摘要】 超级电容器是一种介于电池和传统电容器之间的新型储能器件,具有比传统电容器更高的能量密度及比普通电池更高的功率密度和更长的循环寿命。随着高性能的电化学超级电容器在移动通讯、信息技术、航天航空和国防科技等领域的不断应用,超级电容器越来越受到人们的关注,特别是环保汽车——电动汽车的出现,大功率的超级电容器更显示了其前所未有的应用前景,现已成为世界各国的能源研究的热点。展开这一热点,面对的就是一项研究的重点工程——超级电容器高比容电极材料的开发。本论文根据大量的资料调研,紧跟该领域的国际研究前沿,以碳材料和金属氧化物材料着手,通过选择材料体系,优化电极制作工艺,研制出超级电容器用碳电极和二氧化铅薄膜电极,并组装成电容器单元。将材料表征手段和电化学研究手段相结合,对其性能进行了测试,为研制超级电容器提供实验依据和理论基础。主要研究内容如下:1、采用活性碳作为超级电容器的电极材料,通过探索电极的制备工艺和电容器的组装工艺,利用循环伏安、电化学阻抗谱和恒流充放电等手段,测试了碳基超级电容器的电容特性。为后续新材料的开发奠定基础。2、采用恒电流法沉积二氧化铅薄膜电极,在前人的基础上对制备工艺进行了优化,并借助SEM和XRD研究了二氧化铅电极的结构特性。以二氧化铅电极为正极,活性碳电极为负极,1.28 g·cm^-3H₂SO₄作为电解液,组装成二氧化铅/活性碳混合超级电容器,并研究了其循环伏安、恒流充放电、交流阻抗等电化学特性。结果表明,该混合电容器具有电容特性,电容器工作时,既有双电层电容的贡献,又包含准电容的作用,因此其活性物质比容量高于活性碳双电层电容器,且沉积电流对产物的电化学性能有很大的的影响。在30mA·cm^-2电流密度下沉积的多孔结构二氧化铅电极组成的混合电容器不仅具有很高的比电容99.1 F·g^-1,而且具有良好的循环稳定性,恒流充放电3000次后其容量仍保持在83%以上。3、采用脉冲电流技术沉积二氧化铅薄膜电极,重点研究了脉冲时间,脉冲电流大小对二氧化铅电极材料结构及性能的影响。并借助SEM和XRD对二氧化铅电极材料的结构特性进行了表征。以二氧化铅电极为正极,活性碳电极为负极,1.28 g·cm^-3 H₂SO₄作为电解液,组装成二氧化铅/活性碳混合超级电容器,并研究了其循环伏安、恒流充放电、交流阻抗等电化学特性。结果表明,该混合电容器具有电容特性,电容器工作时,既有双电层电容的贡献,又包含准电容的作用,因此其活性物质比容量高于活性碳双电层电容器,且脉冲沉积条件对产物的结构及电化学性能有很大的的影响。在脉冲时间为0.01 s,间歇时间为0.1 s,脉冲电流密度为25 mA·cm^-2下制备的二氧化铅构成的混合电容器具有很高的比电容109.1 F·g^-1,同时具有良好循环稳定性,经5000次深度循环其比容量仅损失9%。更多还原

【Abstract】 As intermediate systems between conventional capacitors and batteries,supercapacitors have shown many advantageous features.While batteries are capable of storing higher energy density than supercapacitors,they deliver less power;Compared to conventional capacitors, supercapacitors can store higher energy density with tess delivered power.Supercapacitors have shown many potential applications in industrial fields,such as mobile telecommunication, information technology,consumer electronics,aviation & aerospace,military,and so on.Recently the prospect of supercapacitors with high power densities extends their application to various other novel devices such as hybrid capacitor-battery systems used in the electric vehicle,and such hybrid systems have attracted more attention throughout the world.Studies on supercapacitors are mainly focused on the preparation of high performance material and electrode assembly.This dissertation was carried out following the international frontier research,according to many literature materials.With carbon materials and lead dioxide as electrode materials for supercapacitors,by integrating various electrochemical and material preparation methods,this research work has been carried out on investigation of material preparation,electrolyte optimization,electrode preparation,capacitive property and mechanism of double-layer capacitance.The main results are as follows:1.Activated carbons have been used as electrode materials in supercapacitor.By investigating electrode preparation and capacitor assembly technology,using cyclic voltammogram, electrochemical impedance spectrum measurement and constant current charge/discharge methods,capacitive characteristics of carbon supercapacitor are studied.These researches are the basis of novel electrode materials.2.Lead dioxides were prepared by the galvanostatic method.Conditions were optimized in the preparation technology and the influence of the current density on the structure of lead dioxide electrodes investigated by using scanning electron microscope（SEM） and X-ray diffraction（XRD）.Electrochemical performance of the hybrid supercapacitor by using the lead dioxide thin electrode as positive electrode,an AC electrode as negative electrode and 1.28g cm^-3 H₂SO₄ as electrolyte were characterized by using cyclic voltammetry（CV）, electrochemical impedance spectroscopy（EIS） and galvanostatic charge/discharge measurements.The results showed that the hybrid capacitor also exhibited capacitance characteristics.Its capacitance was attributed to activated carbon double-layer capacitor at electrodes interfaces and redox pseudocapacitance.And it demonstrated that current density had large effect on the electrochemical performance of the lead dioxide thin electrode.The hybrid capacitor assembled with lead dioxide prepared at current density of 30 mA·cm-2 as positive electrode and an activated carbon as negative electrode delivered a discharge specific capacitance of 99.1 F·g^-1,and after 3000 cycles the specific capacitance remained 83%of the maximum value.3.Lead dioxides were prepared by the pulsed current techniques.The influence of the pulsed curent and pulsed time on the structure of lead dioxide electrodes was studied by using SEM and XRD.Electrochemical performance of the hybrid supercapacitor by using the lead dioxide thin electrode as positive electrode,an AC electrode as negative electrode and 1.28g cm^-3 H₂SO₄ as electrolyte was characterized by using CV,EIS and galvanostatic charge/discharge measurements.The results showed that the hybrid capacitor exhibited capacitance characteristics.Its capacitance was attributed to activated carbon double-layer capacitor at electrodes interfaces and redox pseudocapacitance.It was demonstrated that pulsed conditions had large effect on the electrochemical performance of the lead dioxide thin electrode.The hybrid capacitor assembled with lead dioxide prepared at pulsed current density of 25 mA·cm^-2,pulsed time and relaxation time as positive electrode and an activated carbon as negative electrode delivered a discharge specific capacitance of 109.1 F·g^-1,and after 5000 cycles the specific capacitance remained 91%of the maximum value.更多还原