电沉积法制备镍、锰氧化物及其超级电容性能的研究

发布时间：2018-07-09 19:17

本文选题：超级电容器 + 电化学沉积　；参考：《兰州理工大学》2011年硕士论文

【摘要】：论文中综述了超级电容器的国内外现状及超级电容器电极材料的最新研究进展,并且制备了超级电容器电极材料,即氧化镍和二氧化锰薄膜电极。以氧化镍和二氧化锰作为超级电容器电极材料,具有可快速高效放电、使用寿命长、温度宽和无环境污染等优点。因此,本文采用简单的电沉积方法,在三维泡沫镍基底上制备氧化镍和二氧化锰纳米薄膜,并将其直接作为超级电容器电极材料,结合多种材料研究方法和电化学测试手段,系统研究了薄膜的结构和电化学性能以及沉积条件与电化学性能之间的关系。具体开展的研究内容如下: 1.以泡沫镍为基底,利用阴极电沉积法制备了三维网状结构的NiO薄膜,系统研究了该薄膜的结构、形貌特征、孔径分布及形成机理,考察了沉积条件如沉积质量和沉积电压对薄膜形貌和电化学性能的影响。研究结果表明:制备的NiO薄膜不仅具有完整均一的三维网状结构,而且具有较高的比表面积,孔径主要分布在8~11 nm左右,比表面积为142 m~2/g。这种特殊的三维网状结构使得NiO薄膜孔隙率增加,渗透性得到改善,有利于促使电解液中的活性离子扩散到电极表面和体相当中,发生氧化还原反应,产生大的法拉第赝电容。同时,发现沉积电位和沉积质量的变化直接影响着薄膜的形貌和电化学性能,当沉积电位为-0.7 V,沉积质量为0.83 mg时NiO薄膜具有最高比容量,在3 A/g的放电电流下其比电容可达1361 F/g,这是目前该材料报道的最高比容量。 2.以泡沫镍为基底,利用阳极电沉积法制备了MnO_2薄膜,系统研究了该薄膜的结构、组成和形貌,结合单因素实验和正交试验方法,考察了电沉积中工艺参数对MnO_2薄膜电化学性能的影响。研究结果表明:MnO_2薄膜结构疏松,呈相互交错的棒状结构,使得孔隙率增加,从而增大了薄膜的比表面积。通过正交实验得出了最优电沉积工艺:沉积电位为0.5 V,醋酸锰浓度为0.25 M,泡沫镍规格为420 g/m~2时制备的MnO_2薄膜具有最高比容量,在5.5 A/g的放电电流下其最大比电容为664 F/g,并具有优异的大功率性能和循环稳定性。 3.本文对恒电位沉积和循环伏安沉积两种方法制备的MnO_2薄膜进行了结构测试分析和电化学测试分析。XRD和SEM测试结果表明:两种方法制备的MnO_2薄膜结构相似,都为ε-MnO_2,但是两者的形貌有很大差异,恒电位法制备的二氧化锰呈棒状,而动电位制备的二氧化锰则呈球状结构。综合循环伏安、恒流充放电、交流阻抗和循环寿命的测试结果表明恒电位法制备的MnO_2薄膜具有更好的电化学性能。所以恒电位沉积方法在构建高性能二氧化锰薄膜方面具有一定优势。
[Abstract]:In this paper, the current situation of supercapacitors at home and abroad and the latest research progress of electrode materials for supercapacitors are reviewed, and the electrode materials of supercapacitors, namely nickel oxide and manganese dioxide thin film electrodes, are prepared. Using nickel oxide and manganese dioxide as electrode materials of supercapacitor, it has the advantages of fast and high efficiency discharge, long service life, wide temperature and no environmental pollution. Therefore, in this paper, nickel oxide and manganese dioxide nanocrystalline films were prepared on three dimensional foamed nickel substrates by simple electrodeposition, and they were directly used as electrode materials for supercapacitors. The structure and electrochemical properties of the films and the relationship between deposition conditions and electrochemical properties were systematically studied. The specific research contents are as follows: 1. Three dimensional netted nio thin films were prepared by cathodic electrodeposition with nickel foam as substrate. The structure, morphology, pore size distribution and formation mechanism of nio thin films were systematically studied. The effects of deposition conditions such as deposition quality and deposition voltage on the morphology and electrochemical properties of the films were investigated. The results show that the nio thin films not only have a complete and uniform three-dimensional reticular structure, but also have a high specific surface area. The pore size is mainly distributed at 811 nm, and the specific surface area is 142 mg / g. This special three-dimensional network structure increases the porosity and improves the permeability of nio films, which is conducive to the diffusion of active ions in electrolyte into the electrode surface and bulk phase, resulting in a large Faraday pseudo-capacitance. At the same time, it was found that the changes of deposition potential and deposition quality directly affected the morphology and electrochemical properties of the films. When the deposition potential was -0.7 V and the deposition mass was 0.83 mg, nio films had the highest specific capacity. At a discharge current of 3 A / g, the specific capacitance can reach 1361 F / g, which is the highest reported specific capacity of the material. MNO _ 2 thin films were prepared by anodic electrodeposition with nickel foam as substrate. The structure, composition and morphology of the films were systematically studied. The single factor experiment and orthogonal test were used to study the structure, composition and morphology of the films. The effect of process parameters on the electrochemical properties of MnO _ 2 thin films was investigated. The results show that the structure of the thin film is loose, and the structure of the thin film is interlaced with each other, which increases the porosity of the thin film and increases the specific surface area of the thin film. The optimum electrodeposition process was obtained by orthogonal experiment: the deposition potential was 0.5 V, the concentration of manganese acetate was 0.25 M, and the specification of nickel foam was 420 g / m ~ 2. The MNO _ 2 thin film had the highest specific capacity. The maximum specific capacitance at 5.5 A / g discharge current is 664 F / g and has excellent high power performance and cyclic stability. In this paper, the structure analysis, electrochemical analysis, XRD and SEM results of MNO _ 2 thin films prepared by potentiostatic deposition and cyclic voltammetry deposition show that the structure of the films prepared by the two methods is similar. Both of them are 蔚 -MnO _ 2, but their morphologies are quite different. Manganese dioxide prepared by potentiostatic method is rod-like, while manganese dioxide prepared by potentiodynamic method is spherical. The measurement results of cyclic voltammetry, constant current charge and discharge, AC impedance and cycle life show that MnO _ 2 thin films prepared by potentiostatic method have better electrochemical performance. Therefore, the potentiostatic deposition method has some advantages in the construction of high performance manganese dioxide films.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TQ153;TM53

【引证文献】