有机系超级电容用活性炭性能的研究以及大容量超级电容器的开发

发布时间：2018-07-06 12:25

本文选题：超级电容 + 活性炭　；参考：《吉林大学》2017年博士论文

【摘要】：随着传统能源的日益消耗以及近年来环境问题逐渐被人们所重视,清洁能源行业得到了飞速的发展,对储能元件的性能也提出了更高的要求,传统的储能元件已经开始显现出其局限性,超级电容器作为新一代储能元件,逐渐走进了人们的视野。本论文着力于超级电容单体性能的提高,研究内容包括集流体表面改性技术对电容单体性能的影响、电极材料涂布厚度对电容单体内阻的影响、活性炭材料比表面积与孔径分布对材料比电容的影响等,在研究结果的基础之上,设计并且制备了不同类型的大容量超级电容器单体。使用了电火花放电的方法处理集流体表面,极大地降低了集流体与电极材料的接触电阻,使得电极片电阻的测量更加精确,在此基础上分析了极片厚度对电容器内阻的影响。为了探究电极材料涂层厚度对电极材料的比电容、能量密度、电容器内阻、峰值功率以及循环性能的影响,制备了不同涂层厚度的样品,使用了恒流充放电(GCD)、循环伏安(CV)、电化学交流阻抗图谱(EIS)等手段对样品进行了较全面的测试,分析实验结果发现:电极材料的比电容、能量密度与电极材料涂层厚度呈现非线性关系,当涂层厚度为88.2μm时,二者达到最大值,分别为122.5 F?g~(-1),38.5 Wh/kg,也就是说,此涂层厚度可以作为能量型超级电容器的最佳电极材料涂层厚度;电容器的内阻、峰值功率以及循环性能与电极材料涂层厚度呈现非线性关系,当涂层厚度为61.1μm时达到最佳,分别为0.126Ω,14.46W,92.9%,此涂层厚度可以作为功率型超级电容器的最佳电极材料涂层厚度;为了从理论上解释内阻与电极材料涂层厚度的关系,建立了一个数学模型来描述电荷在孔隙以及传输通道中的扩散过程,实验结果也充分验证了此模型的可靠性。由模型计算得到,使得内阻最小化的涂层厚度应为53.1μm。测试了四种活性炭样品的比表面积与孔径分布等参数,以及其作为电极材料的比电容。等温吸脱附曲线(Ⅳ型)与密度函数理论(DFT)孔径分布结果显示,虽然四种材料的孔径类型有所区别,但都存在大量的微孔和中孔结构。通过对比各样品的比电容与比表面积,发现比表面积并不是决定材料比电容的唯一标准。因为微孔范围内有很大一部分孔径小于电解液中的带电离子尺寸,所以不能够存储电荷,致使这部分微孔没有贡献电容量。为了确定活性炭材料提供比电容的孔径分布范围,假定活性炭材料的电容量与能够存储电荷的孔隙面积或者孔体积成线性关系,在此基础之上计算了在不同孔径分布下的比表面积和孔体积与比电容的线性相关性,确定了活性炭材料提供电容量的孔径分布为1.2-50nm。在前两章的研究基础上,研究开发了300F软包装、3000F软包装以及4000F铝壳封装的超级电容单体制备工艺流程,包括电极浆料混合、电极材料涂布、极片设计、极耳设计、超声焊接、激光焊接、真空注液等工艺。对制备的超级电容单体进行了电化学性能测试:300F单体在1A放电电流下的实测容量为333F,等效串联内阻为1.5mΩ,能量密度为4.54Wh?kg~(-1),峰值功率密度为25.9kW?kg~(-1);3000F单体在4A放电电流下的实测容量为2950F,等效串联内阻0.375mΩ,能量密度为3.31Wh?kg~(-1),峰值功率密度为8.45kW?kg~(-1);4000F单体在4A放电电流下的实测容量为4258F,等效串联内阻0.43mΩ,能量密度为5.6Wh?kg~(-1),峰值功率密度为7.4kW?kg~(-1),在50A大电流放电时,单体仍保持3609F的电容量,此时内阻为0.44mΩ,能量密度为4.2Wh?kg~(-1),峰值功率密度为7.68kW?kg~(-1)。将国际领先的工业化产品在同样条件下测试,对比实验结果发现,虽然实验室制备的电容器在内阻以及峰值功率密度方面稍差,但是能量密度较高。
[Abstract]:With the increasing consumption of traditional energy and the attention of environmental problems in recent years, the clean energy industry has been developing rapidly, and the performance of energy storage components is also higher. The traditional energy storage element has begun to show its limitations. As a new generation of energy storage components, the supercapacitor has gradually entered the people. This paper focuses on the improvement of the performance of the supercapacitor monomers. The study includes the influence of the surface modification technology on the performance of the capacitor, the influence of the coating thickness on the internal resistance of the capacitor, the influence of the specific surface area and the pore size distribution of the activated carbon material on the material's capacitance, and so on, based on the research results. Different types of large capacity supercapacitor monomers are designed and prepared. The method of electrical discharge discharge is used to deal with the surface of the fluid collector. The contact resistance of the collector and the electrode material is greatly reduced, and the measurement of the resistance of the electrode is more accurate. On this basis, the influence of the thickness of the electrode on the internal resistance of the capacitor is analyzed. With the influence of the thickness of the electrode material on the specific capacitance, energy density, capacitor internal resistance, peak power and cycle performance of the electrode material, the samples with different coating thickness were prepared. The samples were tested by constant current charge discharge (GCD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the experimental junction was analyzed. It is found that the specific capacitance and the energy density of the electrode material have a nonlinear relationship with the thickness of the electrode material. When the thickness of the coating is 88.2 m, the two can reach the maximum value, 122.5 F? G~ (-1), 38.5 Wh/kg respectively, that is to say, the coating thickness can be used as the best electrode material coating thickness for the energy type supercapacitor; the internal resistance of the capacitor, The peak power and the cycle performance are nonlinear with the coating thickness of the electrode material. When the thickness of the coating is 61.1 m, the coating thickness is 0.126, 14.46W, 92.9% respectively. The coating thickness can be used as the best electrode material coating thickness for the power type supercapacitor. A mathematical model is established to describe the diffusion process of charge in the pore and the transmission channel. The experimental results also fully verify the reliability of the model. The thickness of the coating is calculated by the model. The thickness of the coating to minimize the internal resistance should be 53.1 mu m. to test the specific surface area and the pore size distribution of the four kinds of activated carbon samples, as well as its work. For the specific capacitance of the electrode material. The results of the isothermal desorption curve (type IV) and density function theory (DFT) aperture distribution show that although the pore size of the four materials is different, there are a lot of micropores and mesoporous structures. By comparing the specific capacitance and the specific surface of each sample, it is found that the specific surface area is not a determination of the specific capacitance. The only standard. Because a large portion of the pore size is smaller than the charged ion size in the electrolyte, it is not able to store the charge, causing the pore to not contribute to the capacitance. In order to determine the pore size distribution of the activated carbon material, the capacitance of the activated carbon material and the pore surface that can store the charge are assumed. The linear relation between product or pore volume is linear. On this basis, the linear correlation between specific surface area and pore volume and specific capacitance under different pore sizes is calculated. The pore size distribution of activated carbon materials is determined to be 1.2-50nm. on the basis of the first two chapters, and 300F soft packaging, 3000F soft packaging and 4000F aluminum have been developed. The process flow of the shell package supercapacitor single system, including electrode size mixing, electrode material coating, polar chip design, polar ear design, ultrasonic welding, laser welding and vacuum injection, was used to test the electrochemical performance of the prepared supercapacitor. The measured capacity of the 300F monomer in the 1A discharge current was 333F, and the equivalent series internal resistance was measured. For 1.5m Omega, the energy density is 4.54Wh? Kg~ (-1), the peak power density is 25.9kW? Kg~ (-1); the measured capacity of 3000F monomer under 4A discharge current is 2950F, the equivalent series internal resistance 0.375m Omega, the energy density is 3.31Wh? 43M Omega, the energy density is 5.6Wh? Kg~ (-1), the peak power density is 7.4kW? Kg~ (-1). At the time of the 50A large current discharge, the monomer still maintains the capacitance of 3609F, at this time the internal resistance is 0.44m Omega, the energy density is 4.2Wh? The peak power density is the same. The international leading industrial products are tested under the same conditions, and the experimental results found by comparison experiment are found, Although the capacitors prepared in the laboratory are slightly worse in internal resistance and peak power density, the energy density is higher.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM53

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