热膨胀法制备石墨烯及其电容性能的研究

发布时间：2018-01-16 19:35

本文关键词：热膨胀法制备石墨烯及其电容性能的研究　出处：《天津大学》2011年硕士论文　论文类型：学位论文

【摘要】：超级电容器是一种新型储能装置,它具有充电速度快、循环寿命长、温度特性好和绿色环保等特点。电极材料的选择对电化学电容器的性能至关重要。目前对超级电容器的研究主要集中在高性能电极材料的制备上。以石墨烯和石墨烯基复合材料作为超级电容器的电极材料研究了其电化学性能。并针对材料的不同制备工艺研究了其对电容器电化学性能的影响。通过XRD,SEM,TEM,XPS研究了石墨烯及其复合材料的微观形貌,结构特性。通过改变氧化剂用量以及反应时间的方法对Hummers方法进行改性研究。在浓硫酸用量为57.5ml、高锰酸钾为10g、高温反应15min时得到的氧化石墨制备出的石墨烯的比容量最高,在1mA·cm-2的电流密度下电容量可达342F.g1。 Ni(OH)2是一种常用的超级电容器的电极材料,其可以提供很高的比电容。但是由于单纯的Ni(OH)2材料导电性差、比表面比小等缺点不适合用作超级电容器材料。通过与碳材料的复合可以有效改善以上缺点,本文利用氧化石墨烯与Ni(AC)2为原料制备了Ni(OH)2/石墨烯复合材料。该材料表现出良好的赝电容性能,在10mA·cm-2的电流密度下充分活化以后其容量可达680F.g-1经过100次循环以后容量变为663F.g-1衰减量仅为2.5%具有高度的循环可逆性。将碳材料用作有机相中的电容器电极材料,可以使得电容器能够在更宽的电压范围内充放电,提供更高的能量密度。本文通过组装扣电池对石墨烯在有机溶剂中的应用展开研究,测试结果表明石墨烯在1mol·L-1的LiPF6(DMC+EC)中,0.01-3.5V电压范围内,在100mA.g-1的电流密度下首次放电比容量为1228F.g-1,充电比容量为920F.g-1,在经过30次循环充放电以后放电容量仍可达920F.g-1,充电容量可达917F.g-1,表现出良好的循环性能。
[Abstract]:Supercapacitor is a new type of energy storage device, which has fast charging speed and long cycle life. The selection of electrode materials is very important to the performance of electrochemical capacitors. At present, the research on supercapacitors is mainly focused on the preparation of high performance electrode materials. The electrochemical properties of graphene and graphene matrix composites as electrode materials for supercapacitors were studied. The effects of different preparation processes on the electrochemical properties of supercapacitors were studied by XRD. . The morphology and structural properties of graphene and its composites were investigated by SEM and TEM XPS. The modification of Hummers was studied by changing the amount of oxidant and reaction time. When the concentration of sulfuric acid was 57.5 ml, potassium permanganate was 10 g. The specific capacity of graphene prepared by graphite oxide at high temperature for 15 minutes was the highest, and the specific capacity of graphene was up to 342F.g1 at the current density of 1mA 路cm-2. Ni(OH)2 is a commonly used electrode material for supercapacitors, which can provide a high specific capacitance, but because of the poor conductivity of pure Ni(OH)2 materials. The disadvantages such as low specific surface ratio are not suitable for use as supercapacitor materials. These shortcomings can be effectively improved by compounding with carbon materials. In this paper, NiOH2 / graphene composites were prepared by using graphene oxide and Ni(AC)2 as raw materials, which showed good pseudo-capacitance properties. When fully activated at the current density of 10mA 路cm-2, its capacity can reach 680F.g-1 after 100 cycles, and then its capacity becomes 663F.g-1 attenuation of only 2.5% with height. The cyclic reversibility of the. When carbon is used as electrode material of capacitor in organic phase, capacitors can charge and discharge in a wider voltage range. In order to provide higher energy density, the application of graphene in organic solvents was studied by assembling cladding cells. The results show that graphene is in the voltage range of 0.01-3.5V in 1 mol 路L ~ (-1) LiPF6(DMC ECs. Under the current density of 100mA.g-1, the first discharge specific capacity is 1228F.g-1 and the charging capacity is 920F.g-1. After 30 cycles, the discharge capacity can still reach 920 F.g-1, and the charge capacity can reach 917 F.g-1, showing good cycling performance.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TM53

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