The Study Of The Activated Carbon In The Organic System Supercapacitor And The Development Of Large Capacity Supercapacitor

With the increasing consumption of traditional energy and environmental issues having been gradually taken seriously in recent years,the clean energy industry has been rapidly developed,and it leads to higher requirements of the performance of energy storage components.The traditional energy storage components showed its limitations,as a new generation of energy storage components,supercapacitor came to be known into the resercher's vision gradually.In this thesis,one purpose is to improve the performance of the supercapacitor as a component.The research contents includes the influence of the current collector surface modification technology on the performance of the supercapacitor,the influence of the thickness of the electrode materials coating on the internal resistance of the supercapacitor,the influence of the specific surface area and pore size distribution of the activated carbon to its specific capacitance.On the basis of the research results,the design and fabrication of different types of large capacity super capacitor monomer has been made.The contact resistance of the current collector and the electrode material is greatly reduced by using the eletric spark discharge method,which makes the measurement of the resistance of the electrode more accurate.On this basis,the influence of the thickness of the electrode on the internal resistance of the capacitor is analyzed.In order to investigate the effect of the thickness of the electrode materials coating on the specific capacity,energy density,internal resistance,peak power density and cycle performance of the electrode materials,samples with different electrod materials coating thickness were prepared and the samples were tested by means of Galvanostatic Charge Discharge?GCD?,Cyclic Voltammetry?CV?and Electrochemical Impedance Spectroscopy?EIS?.The results show the nonlinear dependence of specific capacitance and energy density of the electrode material on the thickness of the electrode materails coating with the maximum values,which is 122.5 F?g^-1 and 38.5 Wh?kg^-1 respectively when the coating thickness is 88.2?m.And the thickness of the coating can be used as the optimum electrode material coating thickness for the energy type supercapacitor.The resulsts also show the nonlinear dependence of the internal resistance,peak power and cycle performance of the capacitor on the thickness of the electrode materails coating with the maximum values,which is 0.126 ?,14.46 W,92.9% respectively when the coating thickness is 61.1?m.And the thickness of the coating can be used as the optimum electrode material coating thickness for the power type supercapacitor.In order to explain the relationship between the internal resistance and the coating thickness of the electrode matetial theoretically,a mathematical model is established to describe the diffusion process of charge in the pores and the transmission channel.The experimental results also fully verify the reliability of the model.According to the simulation of this model,the minimized internal resistance thickness of the coating should be 53.1 ?m.The parameters such as specific surface area and pore size distribution of four activated carbon samples were tested and their specific capacity as electrode materials were tested.The isothermal adsorption-desorption curve?Type ??and Density Function Theory?DFT?pore size distribution show that although there are differences in the type of pores of the four materials,there are a large number of microporous and mesoporous structures.By comparing the specific capacitance and specific surface area of each sample,it is found that the specific surface area is not the only parameter for determining the specific capacity of the porous materials.Because a large part of the pore size is smaller than the charged ions in the electrolyte,it is not possible to store the charge,so that this part of the micropores do not contribute to the capacitance.In order to determine the pore size distribution range of the active specific surface of the activated carbon material,it is assumed that the capacitance of the activated carbon material is linearly related to the pore area where the charge can be stored.On this basis,the linearity of the specific surface area of different pore size distribution and specific capacity is calculated The pore size distribution of active specific surface area of the activated carbon material was determined to be 1.2-50 nm.On the basis of the previous work,the research and development of 300 F flexible packaging,3000 F flexible packaging and 4000 F aluminum shell packaging super capacitor monomer preparation process is made,including electrode slurry mixing,electrode material coating,electrode design,ultrasonic welding,laser welding,vacuum injection and other processes.The electrochemical performance of the prepared supercapacitor was tested.The measured capacitance of the 300 F monomer at 1A discharge current was 333 F,the equivalent internal resistance was 1.5m?,the energy density was 4.54 Wh?kg^-1,the peak power density was 25.9 kW?kg^-1.3000 F monomer in the 4A discharge current measured capacitance was 2950 F,equivalent series resistance was 0.375m?,energy density was 3.31 Wh?kg^-1,the peak power density was 8.45 kW?kg^-1.4000 F monomer in the 4A discharge current measured capacity was 4258 F,equivalent series resistance was 0.43m?,energy density was 5.6 Wh?kg^-1,the peak power density was 7.4 kW?kg^-1,in 50 A high current discharge,the monomer still maintains the capacitance of 3609 F,the internal resistance of 0.44m?,the energy density of 4.2 Wh?kg^-1,the peak power density of 7.68 kW?kg^-1.The results of the experimental results show that although the capacitors prepared in the laboratory are slightly inferior in internal resistance and peak power density,the energy density is higher than the international leading industrial products.