铜基纳米氧化物的可控制备及超级电容器性能研究

发布时间：2018-02-01 14:42

本文关键词： 超级电容器氧化铜复合材料电化学性能　出处：《重庆大学》2014年硕士论文　论文类型：学位论文

【摘要】：化石能源的过度消耗带来了严重的环境问题和能源危机，为实现可持续发展能源的开发和有效利用，新能源和新型能源装置的研究引起全世界研究者的广泛关注。作为一种新型能量存储装置，超级电容器具有功率密度高、可逆性好、工作温度范围宽、可快速充放电而且循环寿命长、无污染等优点，近年来得到了人们的广泛关注。对于超极电容器来说，影响其电化学性能最关键的因素是电极材料，电极材料的优劣直接决定着超级电容器的性能好坏。金属氧化物由于具有高能量密度、高比电容和极好的可逆性，而被广泛作为超级电容器电极材料。本文采用不同方法合成了不同形貌的CuO及CuO复合纳米结构，并将其用于超级电容器电极材料的研究中。通过X射线衍射仪（XRD）、场发射扫描电镜（FESEM）、透射电镜（TEM）及比表面积测试仪（BET）分析了样品的形貌特征、晶体结构、比表面积和孔结构，并采用循环伏安、恒电流充放电和交流阻抗等测试方法对电极材料的电化学性能进行了研究。其主要研究内容和结论如下：以Cu(NO3)2·3H2O为铜源，四正辛基溴化铵（TOAB）为表面活性剂，氨水和NaOH为沉淀剂，通过常温液相法合成了不同形貌的CuO纳米结构，并考察了形貌对CuO电极材料的电化学性能影响，结果表明，CuO纳米带具有较好的电化学性能，其最高比电容为137F g-1，500次充放电循环后比容能仍能保持88.1%。采用常温液相法制备的CuO纳米花作为基体，通过水热法分别合成了花状CuO/NiO和花状CuO/MnO2的复合纳米结构。研究发现，NiO和MnO2纳米片都均匀的、紧密的覆盖在花状CuO的表面，显著增加了复合材料的比表面积，从而提高了电极材料的电容性能。电化学性能显示，花状CuO/NiO和CuO/MnO2复合材料的比电容分别为280和167.2F g-1，明显高于复合前花状CuO的比电容（65Fg-1），而且复合材料具有良好的大倍率的充放电性能和优异的循环稳定性。以低温水浴法合成的Cu纳米线为基体，与KMnO4水热合成了CuO@MnO2的核壳纳米结构。三电极体系的电化学性能测试结果表明，在0.6Ag-1的电流密度下，CuO@MnO2核壳结构纳米管的比电容能达到276F g-1，经过1000次循环充放电以后，比电容保留率为92.1%，显示了良好的循环稳定性。在两电极的性能研究中，以CuO@MnO2核壳结构作为正极，活化的微波剥离的氧化石墨烯（MEGO）为负极组装成非对称超级电容器元件，其最大的能量密度和功率密度分别能达到22.1Wh kg-1和85.6kW kg-1，显示了其良好的应用前景。本论文中多种铜基氧化物自组装结构的合成思路和方法，为深入研究和开发新颖微观结构的铜基氧化物纳米材料提供了可靠思路。同时，制备的铜基纳米自组装纳米结构显示了优异的电化学性能，，是作为超级电容器电极材料的优选材料。
[Abstract]:Excessive consumption of fossil energy has brought serious environmental problems and energy crisis, for the realization of sustainable development of energy development and effective use. As a new energy storage device, supercapacitors have high power density, good reversibility and wide working temperature range. The advantages of rapid charge and discharge, long cycle life, no pollution and so on, have been widely concerned in recent years. For superelectrode capacitors, the most important factor affecting their electrochemical performance is electrode materials. The performance of supercapacitors is directly determined by the quality of electrode materials. Metal oxides have high energy density, high specific capacitance and excellent reversibility. CuO and CuO nanostructures with different morphologies were synthesized by different methods. It has been used in the study of electrode materials for supercapacitors. The field emission scanning electron microscope (FESEM) was used to study the electrode materials of supercapacitors by using X-ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM). The morphology, crystal structure, specific surface area and pore structure of the samples were analyzed by TEM and BET, and cyclic voltammetry was used. The electrochemical properties of electrode materials were studied by constant current charge-discharge and AC impedance measurements. The main contents and conclusions are as follows: Cu(NO3)2 路3H2O was used as copper source, tetraoctyl ammonium bromide (TOAB) as surfactant, ammonia and NaOH as precipitant. CuO nanostructures with different morphologies were synthesized by liquid phase method at room temperature. The effects of morphology on electrochemical properties of CuO electrode materials were investigated. The maximum specific capacitance is 137F g ~ (-1) F ~ (-1) F ~ (-1). After 500 cycles, the specific capacitance can still be maintained at 88.1g ~ (-1). The composite nanostructures of flower-like CuO/NiO and flower-like CuO/MnO2 were synthesized by hydrothermal method using CuO nano-flowers prepared by liquid phase method at room temperature. Both NiO and MnO2 nanoparticles are uniform and tightly covered on the surface of flower-like CuO, which significantly increases the specific surface area of the composite, thus improving the capacitance performance and electrochemical performance of the electrode material. The specific capacitance of flower-like CuO/NiO and CuO/MnO2 composites was 280 and 167.2 F g-1, respectively, which was significantly higher than that of pre-flowered CuO with specific capacitance of 65 Fg-1). Moreover, the composite has good charge-discharge performance and excellent cyclic stability. The core-shell nanostructures of CuO@MnO2 were synthesized by hydrothermal synthesis of CuO@MnO2 with Cu nanowires synthesized by low-temperature water bath method. The electrochemical properties of the three-electrode system were tested. The specific capacitance of CuOMnO2 core-shell nanotubes can reach 276F g-1 at the current density of 0.6Ag-1, after 1000 cycles. The specific capacitance retention rate is 92.1, which shows good cyclic stability. In the study of the performance of the two electrodes, the CuO@MnO2 core-shell structure is used as the positive electrode. Activated microwave stripping graphene oxide MEGO) is assembled into an asymmetric supercapacitor element for negative electrodes. The maximum energy density and power density can reach 22.1Wh kg-1 and 85.6kW kg-1respectively, which shows its good application prospect. In this paper, a variety of copper-based oxide self-assembly structure synthesis ideas and methods for the in-depth study and development of novel Cu-based oxide nanomaterials. At the same time. Copper based nano self-assembled nanostructures show excellent electrochemical properties and are used as electrode materials for supercapacitors.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB383.1;TM53

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