【作者】 胡艳华；

【导师】 苏中兴；

【作者基本信息】 兰州大学 ， 物理化学， 2010， 硕士

【摘要】 随着世界性的能源危机和环境污染的加剧,人们对节能环保要求越来越高。作为一种新型的能量储存装置—电化学电容器,兼有传统电容器和二次电池的双重功能,一经问世,便受到了人们的极大青睐,成为当前国际性的研究热点。电极材料是决定电化学电容器性能的关键因素,因此,在电化学电容器的研究中,许多工作都是围绕着开发具有高比容量且廉价环保的电极材料而进行的。本论文综述了电化学电容器的基本原理、电极活性材料研究进展以及其应用前景,并以泡沫镍为基底制备了两种电化学电容器电极。利用XRD、FESEM等技术对电极材料进行了晶体结构分析和微观形貌表征。采用恒流充放电、循环伏安(CV)、电化学交流阻抗(EIS)等电化学技术对电极电容性能进行测试。具体开展的主要实验内容如下：1,在前期工作的基础上,以0.1 M Ni(NO3)2水溶液为电解液,采用直流电沉积的方法在泡沫镍基底上,制备了三维Ni(OH)2电极,通过循环伏安(CV)、恒流充放电、电化学交流阻抗(EIS)等电化学技术系统研究了电沉积条件(沉积温度,活性物质Ni(OH)2的负载量)对其电容性能的影响。结果表明：三维Ni(OH)2电极容量受电沉积温度和活性物质的负载量影响显著。当Ni(OH)2的沉积量为0.7 mg,沉积温度为65℃时所得到的三维Ni(OH)2电极容量特性和功率特性最为理想,获得了高达3887 F／g的平均单电极比容量。2,首次在Co(NO3)2水溶液中以泡沫镍为基体采用直流电沉积的方法制备了三维Co(OH)2电极,通过循环伏安(CV)、恒流充放电、电化学交流阻抗(EIS)等电化学技术对不同电沉积条件(沉积温度,活性物质Ni(OH)2的负载量)下制备的一系列的三维Co(OH)2电极进行了测试。在充放电电流密度为4 A/g时,其平均单电极比容量达2469 F/g,当充放电电流密度增加至32A/g时,其平均单电极比容量为2003 F/g,与充放电电流密度为4 A/g相比,其容量保持率高达81.12%,可见三维Co(OH)2电极具有很好的功率特性。更多还原

【Abstract】 With the growth of the world energy crisis and the environmental pollution, there is increasing requirement on the energy saving and environment protecting. Electrochemical capacitor, which is one of the newest innovations in the field of electrical energy storage, combining the advantages of both dielectric capacitors and conventional rechargeable batteries, has attracted much attention and become an international hotspot, once appeared. The electrode material is a key factor which determines the performance of the electrochemical capacitors, therefore, much work focuses on developing electrode materials with high capacity, low cost and environmentally friendly character.In this dissertation, we have reviewed the basic principle of the electrochemical capacitors, the advances of research on electrode materials and the prospects of electrochemical capacitors. Two kinds of electrodes based on nickel foam for electrochemical capacitors were prepared. X-ray powder diffraction (XRD) and field emission scanning electronic microscopy (FESEM) were used to characterize the structure and morphology of the coatings on the electrodes. The cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectra (EIS) were used to systematically investigate the capacitance of the electrodes. The main content is as follows:(1) Three-dimensional Ni(OH)2 coatings were directly electrodeposited on nickel foam from aqueous solution of Ni(NO3)2 for electrochemical capacitor electrodes. The cyclic voltammetry (CV), chronopotentiometry, electrochemical impedance spectra (EIS) were used to systematically study the effects of electrodeposition parameters such as deposition temperatures and active material loading on the electrochemical capacitor behavior. The investigation showed that the deposition temperatures and active material loading have obviously affected the capacitance of the three-dimensional Ni(OH)2 electrode. At a charge/discharge current density of 4 A/g, an average specific capacitance as high as 3887 F/g can be achieved at the optimum deposition temperature of 65℃with the Ni(OH)2 loading of 0.7 mg.(2) Three-dimensional Co(OH)2 coatings were directly electrodeposited on nickel foam from aqueous solution of Co(NO3)2 for electrochemical capacitor electrodes. The cyclic voltammetry (CV), chronopotentiometry, electrochemical impedance spectra (EIS) were used to systematically study the effects of deposition temperatures and the Co(OH)2 loading on the electrochemical capacitance of the electrode. An average specific capacitance as high as 2469 F/g was obtained at a charge/discharge current density of 4 A/g, and the average specific capacitance was still up to 2003 F/g when the charge/discharge current density augments to 32 A/g, which is 81.12% of the average specific capacitance at the charge/discharge current density of 4 A/g. Thus it is obvious that the three-dimensional Co(OH)2 electrode has excellent electrochemical capacitance property.更多还原