钴酸镍及其复合材料的控制合成与电化学性能研究

发布时间：2018-05-02 17:34

本文选题：超级电容器 + 钴酸镍　；参考：《重庆大学》2015年硕士论文

【摘要】：超级电容器是一种新型的绿色能量存储装置,迄今,已引起世界各国研究者的广泛关注。对于超级电容器而言,电极材料的性质对其电化学性能有着至关重要的影响。因此对超级电容器电极材料的设计和研究具有重要意义。三元金属氧化物钴酸镍(Ni Co2O4)因其高的电化学活性、好的导电率以及环境友好等特点而被认为是非常有前景的超级电容器电极材料。然而,在实际的电极反应中,由于Ni Co2O4电极材料的利用率低、孔结构不均匀以及结构不稳定等因素大大降低了Ni Co2O4的应用。因此,本论文通过研究设计新颖的Ni Co2O4纳米多孔结构和复合电极材料,来增加其比表面积和反应动力学性质,在保持结构稳定性的同时还能有效提高电极材料利用率和电荷存储能力。主要研究内容和结论如下:首先,利用简单、温和的水热法,在没有使用模板和表面活性剂的条件下成功合成蒲公英状的Ni Co2O4微球,并考察了其电化学性能。测试结果表明,在电流密度为1 A g-1时,Ni Co2O4微球的比电容为372 F g-1,当电流密度从1增加到10A g-1时,其比电容仍有84.1%的保持率。并且在电流密度为5 A g-1下循环2000次后其比电容保持率为88.3%。其次,利用水热法和化学共沉淀法成功制备出Ni Co2O4-Mn O2和Co3O4-Mn O2复合纳米线,使用XRD、SEM、TEM和BET等技术对其成分和结构进行了表征,并对比了Ni Co2O4-Mn O2和Co3O4-Mn O2纳米线的超级电容器性能。测试结果表明Ni Co2O4-Mn O2纳米线具有大的比表面积、高的孔隙率以及好的结构稳定性。且Ni Co2O4-Mn O2纳米线三电极体系下表现出较好的电化学性能,其比电容为343 F g-1,在5 A g-1的电流密度下循环3000次后,容量保持率为89.7%。最后,以Cu纳米线作为载体,利用化学共沉淀法成功制备出Cu/Cu Ox/Ni Co2O4核壳纳米线。金属Cu可以增加复合材料的导电性,从而提高电极材料的电子迁移率。三电级体系下的电化学性能测试表明,在1 A g-1的电流密度下,Cu/Cu Ox/Ni Co2O4核壳纳米线的比电容达到578 F g-1,经过6000次的充放电后,比电容保留率为98.9%,表现出良好的循环稳定性能。在两电极体系的研究中,Cu/Cu Ox/Ni Co2O4//AG非对称超级电容器件最大能量密度和功率密度分别达到12.6 Wh kg-1和4.94 k W kg-1,且在2 A g-1的电流密度下循环10000次后仍有98.2%的电容保持率,表现出良好的应用潜能。本论文围绕Ni Co2O4电极材料,利用纳米材料自组装的思路制备出三维Ni Co2O4微球和两种不同的一维Ni Co2O4核壳纳米线,并深入研究了其超级电容器性能,为深入开发和研究Ni Co2O4材料在储能领域的应用提供了可靠的思路。同时,制备得到的Ni Co2O4复合材料表现出优异的电化学性能,是目前能量存储领域的优选材料。
[Abstract]:Supercapacitor is a new type of green energy storage device, which has attracted the attention of researchers all over the world. For supercapacitors, the properties of electrode materials have an important effect on their electrochemical performance. Therefore, it is of great significance for the design and research of electrode materials for supercapacitors. Due to its high electrochemical activity, good conductivity and environmental friendliness, the ternary metal oxide Nickel Cobalate Nickel Co _ 2O _ 4 is considered to be a promising electrode material for supercapacitors. However, in the actual electrode reaction, the application of Ni Co2O4 is greatly reduced because of the low utilization ratio of Ni Co2O4 electrode material, the uneven pore structure and the unstable structure. Therefore, in order to increase the specific surface area and reaction kinetics, a novel Ni Co2O4 nano-porous structure and composite electrode materials were designed in this paper. The efficiency of electrode material utilization and charge storage can be improved effectively while maintaining structural stability. The main contents and conclusions are as follows: firstly, the dandelion like Ni Co2O4 microspheres were successfully synthesized by a simple and mild hydrothermal method without templates and surfactants, and their electrochemical properties were investigated. The results show that the specific capacitance of Ni Co2O4 microspheres is 372F g-1 when the current density is 1 A g ~ (-1). When the current density is increased from 1 to 10 A g ~ (-1), the specific capacitance still has a retention rate of 84.1%. When the current density is 5 A g ~ (-1), the specific capacitance retention rate is 88. 3 after 2000 cycles. Secondly, Ni Co2O4-Mn O 2 and Co3O4-Mn O 2 composite nanowires were successfully prepared by hydrothermal and chemical coprecipitation methods. The composition and structure of Ni Co2O4-Mn O 2 and Co3O4-Mn O 2 nanowires were characterized by BET and TEM techniques. The properties of supercapacitors of Ni Co2O4-Mn O 2 and Co3O4-Mn O 2 nanowires were compared. The results show that Ni Co2O4-Mn O 2 nanowires have large specific surface area, high porosity and good structural stability. The specific capacitance of Ni Co2O4-Mn O 2 nanowires was 343F g -1. After 3000 cycles at 5 A g ~ (-1), the capacity retention rate was 89.7%. Finally, Cu/Cu Ox/Ni Co2O4 core-shell nanowires were successfully prepared by chemical coprecipitation with Cu nanowires as carrier. Metal Cu can increase the electrical conductivity of the composite and improve the electron mobility of the electrode material. The electrochemical performance tests of three-level system show that the specific capacitance of Cu / Cu Ox/Ni Co2O4 nanowires reaches 578F g-1 at the current density of 1A g ~ (-1). After 6000 times of charge and discharge, the specific capacitance retention rate is 98.9, which shows good cyclic stability. In the two-electrode system, the maximum energy density and power density of Cu / Cu Ox/Ni Co2O4//AG asymmetric supercapacitor are 12.6Wh kg-1 and 4.94kg-1, respectively, and the capacitance retention is 98.2% after 10000 cycles at the current density of 2Ag-1. Demonstrate good application potential. In this paper, three dimensional Ni Co2O4 microspheres and two different one-dimensional Ni Co2O4 core-shell nanowires were prepared by self-assembly of nanomaterials around Ni Co2O4 electrode materials, and the properties of supercapacitors were studied. It provides a reliable way to develop and study the application of Ni Co2O4 materials in the field of energy storage. At the same time, the prepared Ni Co2O4 composites exhibit excellent electrochemical properties and are the best materials for energy storage at present.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ138.13;TM53

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