| With the rapidly growing demand of energy and the continuous consumption of fossil fuels,nowadays society is facing more and more serious energy and environmental problems.In order to solve these problems,for one thing,renewable and clean energy sources such as solar energy,wind energy,and thermal energy must be developed,and supercapacitors are often used as energy storage devices for clean energy because of their high input/output power and fast charge/discharge characteristics;for another,saving and making efficient use of energy are necessary,and electrochromic devices are widely used in buildings,vehicles and other facilities to play an energy-saving role by adjusting their color and emissivity（transmittance）.Therefore,this thesis mainly studies devices with dual functions:electrochromism and energy storage.The specific research content is as follows:Firstly,an electrode with symmetrical structure based on the stress compensation effect was designed and prepared.Supercapacitors or electrochromic devices with flexible substrates were prone to warp due to unbalanced forces during electrodeposition of active materials polyaniline,which affected the quality of the active material on the electrode surface.In this thesis,a symmetrical electrode based on the stress compensation effect was designed and prepared.Flexible nylon was used as the substrate,and electrodes were formed by electrodepositing polyaniline on both sides of nylon at the same time.Through this method,high uniformity of PANI film and good adhesion between PANI and the substrate were achieved.Then,an integrated device was designed and prepared.In order to further reduce the volume of the device and increase the volume power and energy density,an integrated device based on porous nylon was presented in this thesis.Au was deposited on both sides of the nylon membrane by thermal evaporation.The shadow effect of thermal evaporation ensured that the Au layer at each side was physically disconnected.Polyaniline was grown on both sides of the nylon substrate,and the gel electrolyte penetrated the nylon substrate through vacuum filtration to form the device.The thickness of the device was approximately equal to that of the nylon substrate.Compared with the conventional assembled device,the volume of the integrated one was greatly reduced and the flexibility was enhanced,therefore the device could work normally in a rolled state.The areal specific capacitance of a single electrode of the device was 341.7 m F cm-2 at a current density of 0.25 m A cm-2;the volume energy density was 3.4 m Wh cm-3 with a volume power density of 147.8 m W cm-3.The device showed good cycling stability and the capacitance retention was 93.2%after 6500 cycles.Besides,a self-powered energy harvesting system was designed to make use of the dual functions of the device.The energy level of the devices could be intuitively judged by the current color of the devices,which provided a feasible solution for the application of dual-function devices.Finally,a simple way to carbonize the nylon substrate was proposed to effectively increase the power and energy density of the device.During the preparation of the assembled supercapacitor,the nylon substrate could be carbonized by controlling the temperature and humidity environment.New products were found after carbonization through Raman spectroscopy analysis.Both the new products and polyaniline could be used as active materials,thus improving the power and energy density of the device. |
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