Design,Process Optimization And Performance Study Of Flexible Packaging Supercapacitors

Supercapacitors are widely used in electric vehicles,aerospace,national defense,information technology and other fields due to their advantages such as fast charging and discharging speed,long service life and environmental friendly.So far,the electrode materials of commercialized supercapacitors are mainly based activated carbon.Although the materials used in the supercapacitors are very settled and mature,different supercapacitors by different manufacturing techniques have huge variations in energy density,power density and stability.It is of great significance to develop advanced capacitor production technology.In addition,the optimization results of this project were expanded to prepare 200 F medium and large capacity flexible packaging super capacitor,and the temperature characteristics are also systematically studied.The specific research content is as follows:(1)The critial electrode material of supercapacitors was prepared by wet coating process.The thickness,conductivity and density of porous carbon electrode directly affect the effective adsorption and polarization of the ionic layer formed in the double-layer capacitance.The influence of the coating thickness,compaction degree,the type and amount of conductive additives on the electrode was discussed.The results demonstrated that the device displayed the excellent electrochemical properties with a low resistance of 0.32 ? and a specific capacitance of 25 F/g the SuperC45 was used as the conductive agent and the electrodes possessed a thickness of 0.35 mm.(2)On the basis of optimizing the electrode material and dosage,we took 1-ethyl-3-methylimidazole tetrafluoroborate ionic liquids into account to enhance work voltage window and accompanying with the mixture of anhydrous acetonitrile to solve the problem of high viscosity of the ionic liquid itself.Through exploring the different proportions,the volume ratio of ionic liquid to acetonitrile is 1:3,the internal resistance of the device is the minimum,and the cycle stability and charge-discharge curve of the device are the best.(3)On the basis of studying the influence of different layers of electrodes on device performance,a-100F-degree flexible packaging super-capacitors were manufactured.Further,large-capacitive flexible packaging supercapacitors were prepared by enlarging the size of electrode sheets,and the devices were electrochemically measured at room temperature.Meanwhile,the charging and discharging character and self-discharging behavior at different temperatures were also evaluated at different temperatures.And the results showed that with increasing the temperature,the capacitance of the device increases while the self-discharge behavior also become severe.