石墨烯和金属氧化物电极材料及其非对称结构超级电容器研究

发布时间：2018-09-12 09:37

【摘要】：超级电容器是新型储能材料领域研究热点之一，具有高功率密度，但是其能量密度较低，成为制约其应用的瓶颈。因此，提高超级电容器的能量密度备受关注。本文主要从提高工作电压范围(V)和电极材料的比电容(C)两个途径开展研究，分别制备了具有较宽电位窗口以及高比电容的电极材料，并组装成非对称结构超级电容器，以实现超级电容器的能量密度的提升。已取得的研究结果如下：通过化学法制备了石墨烯，石墨烯的电位窗口较宽，达到-1.1-0V，并用于非对称超级电容器的负极材料。为了提升其比电容，我们采用一种简单的水解法制备Fe3O4/rGO复合物，由于Fe3O4和rGO的协同效应，复合物的比电容得到了明显提高，在循环10000次后比电容保持在98%。同时研究表明复合物中Fe3O4和rGO的质量比例会明显影响复合物的电化学性能。我们通过一种快速、简单的方法合成了高比电容的NiCo2O4纳米材料，并用于非对称超级电容器的正极材料。由于NiCo2O4独特的纳米结构而产生了非常高的比电容，在1A g-1时的比电容达到1274.3F g-1，当电流密度增加到20A g-1时比电容为1010.9F g-1，表明具有高倍率特性。采用石墨烯做负极材料，NiCo2O4做正极材料，组装了Graphene//NiCo2O4非对称结构超级电容器。非对称结构超级电容器将石墨烯负极材料（功率源）较宽的电位窗口与NiCo2O4正极材料（能量源）的高比电容结合起来。结果表明，非对称超级电容器器件的电位窗口可以达到1.6V，在0.5Ag-1的电流密度下，比电容达到69.5F g-1。在循环1000次后，，比电容依然保持在大约80%。在功率密度为400W kg-1时，能量密度可以达到24.7Wh kg-1，显示出良好的应用前景。
[Abstract]:Supercapacitor is one of the research hotspots in the field of new energy storage materials. It has high power density, but its low energy density has become a bottleneck restricting its application. Therefore, increasing the energy density of supercapacitor has attracted much attention. Electrode materials with wide potential window and high specific capacitance were prepared and assembled into asymmetric supercapacitors to enhance the energy density of supercapacitors.
Graphene was prepared by chemical method. Graphene has a wide potential window of -1.1-0V and is used as the anode material of asymmetric supercapacitors. In order to improve its specific capacitance, a simple hydrolysis method was used to prepare Fe3O4/rGO composite. Due to the synergistic effect of Fe3O4 and rGO, the specific capacitance of the composite was obviously improved and the composite was recycled. The specific capacitance remained at 98% after 10000 cycles. The mass ratio of Fe_3O_4 and rGO in the composites significantly affected the electrochemical properties of the composites.
NiCo2O4 nano-materials with high specific capacitance were synthesized by a rapid and simple method and used as cathode materials for asymmetric supercapacitors. Due to the unique nanostructure of NiCo2O4, very high specific capacitance was produced. The specific capacitance reached 1 274.3 Fg-1 at 1A g-1 and 1010.9 Fg-1 at 20A g-1 current density. 1, indicating high rate characteristics.
Graphene//NiCo2O4 asymmetrical supercapacitor was assembled using graphene as anode material and NiCo2O4 as cathode material. The asymmetrical supercapacitor combines the wide potential window of graphene anode material (power source) with the high specific capacitance of NiCo2O4 cathode material (energy source). At the current density of 0.5Ag-1, the specific capacitance can reach 69.5Fg-1. After 1000 cycles, the specific capacitance remains at about 80%. At the power density of 400 W kg-1, the energy density can reach 24.7Wh kg-1, showing a good application prospect.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM53

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