【作者】 陈雅桃；

【导师】 何平；

【作者基本信息】 西南科技大学 ， 分析化学， 2011， 硕士

【摘要】 超级电容器是一种新型的电化学能量储存装置。与传统的电容器相比,超级电容器具有较高的功率密度、较长的循环寿命、低的等效串联电阻和对环境无污染等一系列的优点。它在电动汽车、航空航天、笔记本电脑和军事等方面都发挥重要的作用。因此,近年来对超级电容器的研究开发成为一个热点。在各种电极材料研究中,金属氧化物吸引了广泛兴趣。本文制备了金属氧化物基电极材料,采用X射线衍射法和扫描电子显微镜对制备材料微观结构和形貌做了表征;通过掺杂其他材料,采用循环伏安法、计时电位法和电化学阻抗等研究了所制备电极材料的电化学性能。主要研究内容和创新点归纳如下:（1）以氧化还原法制备MnO₂,溶胶-凝胶法制备SnO₂。研究了SnO₂掺杂MnO₂复合电极在KCl溶液中的电化学性能。当活性物中SnO₂的含量为10 wt%时,该复合电极的比容量为302.1 F/g,多次充放电测试后,其电容性能相当稳定。（2）以共沉淀法制备Co₂SnO₄粉末。形貌分析表明所制备的材料是三维纳米尖晶石球状结构。考察了Co₂SnO₄/AC复合电极在KCl电解液中的电化学性能。当Co₂SnO₄含量为25 wt%,该复合电极的比容量为285.3 F/g,1000次循环充放电后比容量衰减了4.2%。与活性炭电极相比,该复合电极不仅比容量大大提高,而且循环稳定性也得到改善。（3）以低温固相反应法制备Co₂O₃掺杂MnO₂。研究了其作为超级电容器电极材料的电化学性能。在1.0 mol/L KCl溶液中,当Co₂O₃掺杂MnO₂复合电极中,Co含量为2.3 wt%时比容量达到340.1 F/g。1000次循环后比容量衰减到291.1 F/g,减少到最初的85.6%。通过分析反应前后的电化学阻抗图得出,电极材料的性能相当稳定,电化学测试没有引起其微观结构的改变。更多还原

【Abstract】 Supercapacitor is a new type of electrochemical energy storage devices. Compared with traditional capacitor, it can provide high energy density, long cycle life, low equivalent series resistance and good environmental compatibility, and so on. It can play an important role in the fields such as electric vehicles, space flight technology, portable computer and military field, etc.. Therefore, it becomes a hot topic to study supercapacitor. Transition metal oxides with various oxidation states have received much interest. In this thesis, MO_x-based electrode materials were prepared. The microstructural characterizations and morphological of as-prepared materials were investigated by X-ray diffraction and scanning electron microscopy, respectively. Cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy were used to evaluate the electrochemical properties.The main contributions and innovations of this thesis are as follows: （1） Redox reaction and sol-gel method were used to prepare MnO₂ and SnO₂, respectively. According to different weight ratio, MnO₂ and SnO₂ were mixed as electrode materials. The electrochemical properties for SnO₂-modified MnO₂ composite electrode were evaluated in KCl solution. It was shown that the composite electrode had excellent properties in capacitance, and the specific capacitance of single electrode with 10 wt% SnO₂ was up to 302.1 F g-1. Furthermore, SnO₂-modified MnO₂ composite electrode exhibited a very stable capacitance after repeating cycles compared to that of the separate MnO₂ or SnO₂ electrode.（2） Co₂SnO₄ was synthesized by co-precipitation method. The spherical beads with three-dimensional nanostructure were depicted by scanning electron microscopy. The electrochemical performance of Co₂SnO₄/AC composite electrode was investigated in KCl solution. It was shown that the composite materials with 25 wt% Co₂SnO₄ had excellent specific capacitance up to 285.3 F/g, and decrease 4.2% of initial capacitance after 1000 cycles. Compared with activated carbon electrode, capacitance performances and cyclic stability of the composite electrode had been noticeably improved.（3） Co₂O₃-doped MnO₂ was prepared by solid state reaction at low temperature. The electrochemical performance was evaluated for Co₂O₃-doped MnO₂ composite electrode. It was found that composite electrode with 2.3 wt% Co had excellent properties in specific capacitance up to 340.1 F/g in 1.0 mol/L KCl aqueous solution. Furthermore, the specific capacitance could keep 291.1 F/g event after 1000 cycles, presenting high operation stability in a continuous charge/discharge process. The stability of electrode materials was studied by electrochemical impedance spectroscopy. It was demonstrated that electrochemical test did not induce significant structural or microstructure changes of electrode active materials, which could be attributed to the co-effect of cobalt doping.更多还原