镍、钴改性活性炭及电化学性能研究

发布时间：2018-07-01 19:27

本文选题：活性炭 + 复合物　；参考：《电子科技大学》2015年硕士论文

【摘要】：作为超级电容器的电极材料,活性炭由于其导电性较差和仅仅以双电层原理产生较低的比容量,在实际应用中受到较大程度的限制。理论上,用镍、钴改性的活性炭复合电极材料在比容量方面,相比于单一的碳基电极材料会有显著提升。另外,利用化学性质较稳定的无机金属导电盐可以提高复合物的电导率。在活性炭与镍、钴的复合物中,活性炭在既充当了主体支架,还起着为电子传输提供通道的作用。金属氧化物和无机导电金属盐则提供较高的比容量和电导率。三者的协同作用可以有效地提高复合物的导电性、比容量、能量密度和循环性能等。本论文主要以超级电容器专用活性炭为原料,利用镍、钴的氧化物以及无机导电金属盐对活性炭进行复合,制备活性炭复合电极材料。并通过扫描电镜测试、X射线衍射测试、高倍透射电镜测试、循环伏安测试和恒流充放电测试等,研究了不同制备工艺以及不同条件下的活性炭复合物的物理性能和电化学性能。1.AC@LNO/NiO复合电极材料性能的研究:(1)为了提高活性炭材料的电化学性能,调节La/Ni的比例,制备了不同的AC@LNO/NiO复合物。当La/Ni的比例为1:2时,AC@LNO/NiO的阻抗为2.97?,其导电能力在纯活性炭基础上提高了一倍。最大的能量密度和功率密度分别为70.37 Wh/kg和32.40 kW/kg。在循环伏安测试中,当扫描速率为1 mV/s时,1:2AC@LNO/NiO复合物的比容量为710.48 F/g。(2)以LNO为导电物质。根据液相沉积和热分解次数的不同,制备出不同纳米结构的AC@LNO/NiO复合物,以提高碳基材料的比容量和电导率。经过两次浸泡和烧结过程后,在S2中的金属氧化物颗粒的结晶性最好,其连续均匀地沉积在活性炭表面上形成更好的多孔结构。当扫描速率为1 mV/s时,S2的比容量为652.19 F/g。S2具有优于S1和S3的导电性。在AC、La2NiO4和NiO的协同作用下,S2的电化学性能明显优于纯活性炭。2.AC@LCNO/Co3O4复合电极材料的性能:LCNO是具有类似于LNO结构的具有良好导电性的无机导电金属盐。将LCNO和Co3O4构成复合金属氧化物,控制镍和钴的质量分数之比,对活性炭进行复合。当镍的质量分数为15%时,活性炭表面上的金属氧化物膜更加均匀,具有最大的比表面积。在1 mV/s时,15%复合物的比容量值为739.42 F/g。15%复合物的电化学稳定性较好,在5000个充放电循环后,产生15.91%的比容量衰减。
[Abstract]:As the electrode material of supercapacitor, activated carbon is limited to a great extent in practical application because of its poor conductivity and the low specific capacity produced only by the principle of double layer. In theory, the specific capacity of activated carbon composite electrode materials modified with nickel and cobalt is significantly higher than that of single carbon based electrode materials. In addition, the electrical conductivity of the complex can be improved by using inorganic metal conductive salts with stable chemical properties. In the complexes of activated carbon with nickel and cobalt, activated carbon not only acts as the main scaffold, but also acts as a channel for electron transport. Metal oxides and inorganic conductive metal salts provide higher specific capacity and conductivity. The synergistic effects of the three factors can effectively improve the conductivity, specific capacity, energy density and cycling performance of the composites. In this paper, the activated carbon composite electrode material was prepared by using nickel, cobalt oxides and inorganic conductive metal salts as raw materials. The X-ray diffraction test, high power transmission electron microscope, cyclic voltammetry and constant current charge-discharge test were used. The physical and electrochemical properties of activated carbon composites under different preparation processes and different conditions were studied. 1. The properties of AC LNO / NiO composite electrode materials were studied: (1) in order to improve the electrochemical properties of activated carbon materials, adjust the ratio of La / Ni, Different AC@ LNO- / nio complexes were prepared. When the ratio of La / Ni is 1:2, the impedance of ACLNO- / nio is 2.97%, and its conductivity is twice as high as that of pure activated carbon. The maximum energy density and power density are 70.37 Whkg and 32.40 kW / kg, respectively. In cyclic voltammetry, when the scanning rate is 1 MV / s, the specific capacity of 1: 2 AC @ LNO / nio complex is 710.48 F / g. (2) LNO is used as conductive material. According to the different times of liquid deposition and thermal decomposition, ACLNO-NiO composites with different nanostructures were prepared to improve the specific capacity and conductivity of carbon-based materials. After two soaking and sintering processes, the crystallinity of metal oxide particles in S2 is the best, and a better porous structure is formed on the surface of activated carbon by continuous and uniform deposition. When the scanning rate is 1 MV / s, the specific capacity of S 2 is 652.19 F / g 路S2, which is superior to that of S 1 and S 3. Under the synergistic action of ACU La2NiO4 and nio, the electrochemical performance of SiS 2 is obviously superior to that of pure activated carbon. 2. The performance of AC LCNO / Co 3O 4 composite electrode material is that the structure of AAC LCNO / Co 3O 4 composite electrode is a kind of inorganic conductive metal salt with good conductivity similar to that of LNO. Composite metal oxides were formed by LCNO and Co _ 3O _ 4, and the ratio of nickel to cobalt was controlled to compound activated carbon. When the mass fraction of nickel is 15, the metal oxide film on the surface of activated carbon is more uniform and has the largest specific surface area. At 1 MV / s, the specific capacity of the complex is 739.42 F / g. 15%. The electrochemical stability of the complex is good. After 5 000 charge-discharge cycles, the specific capacity of the complex decreases by 15.91%.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ424.1;TM53

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