Capacitance Characteristics Of Porous Carbon And The Hybrid Energy Storage Performance Of Zinc/Carbon Electrochemical Device

With the rapid development of modern electronic equipment and electric vehicle, promote of energy density together with charge and discharge speed of electric vehicles battery are put forward. To solve this problem, these studies focus on supercapacitor and secondary battery. The supercapacitor is charging and discharging speed is fast but the energy density is low, while the secondary battery's cycle life is short and charging speed is slow. In this paper the study of electric vehicles battery, which combine the advantages of both super capacitor and secondary battery is proposed. By use of electrodeposited zinc as negative electrode and porous carbon capacitance as cathode the new zinc carbon electrochemical energy storage device integrated the advantages of secondary batteries and supercapacitors, showing the advantage of quick charge, large capacity and long cycle life. The core issue of this study is characteristics of the positive and negative electrode materials of the zinc carbon electrochemical energy storage device and the electrode process. The main researches of this paper are as follows:In this paper, three-electrode system is used to study zinc-ion in copper electro deposition process and using SEM, XRD, constant current charge discharge, Tafel, CV, EIS test method to study KOH concentration, ZnO concentration and temperature of electrolyte and current density's influence of electric electro deposition of zinc. Experimental results show that electric deposition of zinc electrode works the best with electrolyte group:6 mol L-1 KOH+0.4 mol L-1 ZnO, the zinc electrode in 20 mV s-1 scanning speed and in 1000 times cyclic voltammetry and the circulation curves are almost overlapped together. Indicating that the electro deposition of Zn electrode with excellent electrochemical performance. The electrochemical properties of various carbon materials in alkaline ZnO solution were investigated by using the three-electrode system, with the test methods of SEM, TEM, XRD, constant current charge discharge, CV and EIS. The results show that the porous capacitive carbon is the best cathode material in the alkaline ZnO solution. Under the current density of 1000 mA g-1 and 6 mol L"1 KOH solution, the optimum voltage window for the carbon electrode is 0.4-1.4 V, which provides up to 312 F g-1 specific capacitance with a more than 10000 cycles of cycle life.Base on the experimental results, futher study using porous carbon electrode with electrodeposited zinc electrode assemble a carbon zinc energy storage device and the effects of electrode thickness, electrolyte concentration and operating temperature on the electrochemical properties of the electrode were systematically studied. Optimization experiments show that the electrochemical energy storage device has the ability of 3.6 s ultrafast charging and the cycle life up to 20000 times.