Electrochromic Device Based On Ionic Liquid

Electrochromic phenomenon refers to the reversible change of optical absorbance or reflectance of a material in visible and/or infrared regions under suitable electrical fields.Electrolytes play an indispensable role as the prime ionic conduction medium in various electrochemical devices, such as lithium batteries, dye-sensitized solar cells,supercapacitors and electrochromics devices.Among various types of electrolytes, solid polymer electrolytes(SPEs) have attracted wide attention due to the concerns about dimension control, safety, and long-term stability issues of conventional liquid electrolytes. The incorporation of room-temperature ionic liquids(ILs) into polymer electrolytes to prepare solvent-free,nonvolatile, and highly conducting polymer electrolytes has been proposed as a promising approach to overcome the possibility of leakage, evaporation, and explosion of the electrolytes.Thus, the IL-based electrolytes could potentially exhibit higher ionic conductivity and better long-term stability than conventional solvent-containing gel electrolytes, and have no detrimental effect on the electrochemical devices.We deposited polyaniline, tungsten trioxide, prussian blue films respectively on transparent conductive glass FTO through electrochemical method. A variety of methods like Raman and FE-SEM were used to examine the structure and composition of the electrochromism films. Electrochemical method were used to prove the electrochemical properties in ionic liquids. According to the principle of complementary between the anode color materials and cathode color materials, we design the electrochromic device based on ionic liquid and measure electrochromic property of the device, and calculate the efficiency of coloring.The main work includes the following several parts:1. The preparation and characterization of polyaniline films( 1) We deposited PANI films on transparent conductive glass FTO by electrochemical cyclic voltammetry at different proton acid. Raman and FE-SEM were used to examine the structure and composition of the PANI electrochromism films to prove that the different shape structure of polyaniline film may affect films,performance in ionic liquids.( 2) Ultraviolet-visible spectrophotometer were used to measure the electrochromic parameters of PANI films through three electrode system in ionic liquids, it is concluded that the micro emulsion polymerization deposition electrically induced discoloration of polyaniline film electrically induced discoloration in ionic liquid has the very good response. Microemulsion sedimentary polyaniline film has the very good response in ionic liquids.2. Polyaniline – tungsten electrochromic device based on ionic liquids( 1) Tungsten trioxide sol were preparation by chemical reaction. Tungsten trioxide sol as precursor, electrochemical deposition tungsten oxide films and analyze the morphology of WO3 film.( 2) Using complementary tungsten oxide films and polyaniline films as electrode materials, fabricate the electrochromic devices. This device can be determined through electrochemical- ultraviolet spectrophotometer. The maximum efficiency is 176 cm2 C-1. Color and bleach response time is 4s and 5s, respectively.3. Tungsten- prussian blue electrochromic device response controlled by an in situ polymerized ionic liquid based gel electrolyte(1)The preparation of ionic liquid gelIonic liquid gel were preparation by in situ polymerization method. Determine the ionic conductivity of the gel under different proportion to get the best proportion of the ionic liquids gel.(2)The preparation of Prussian blue filmThrough the method of constant current deposited Prussian blue film, andanalyzes its morphology and composition.(3)Fabrication of WO3-PB electrochromic devices based on ionic liquid gelA WO3-PB solid-state electrochromic device was assembled by in situ polymerized ionic liquid. This device can be determined through electrochemical-ultraviolet spectrophotometer. The maximum efficiency is 190cm2C-. Color and bleach response time is 4.5s and 4.0s, respectively.4. The electrochromic of PANI/WO3 based on ionic liquids(1)The preparation of PANI/WO3We deposited PANI/WO3 films on transparent conductive glass FTO by electrochemical cyclic voltammetry.(2)The electrochromic PANI/WO3 based on ionic liquidsThis device can be determined through electrochemical- ultraviolet spectrophotometer. The maximum efficiency is 118cm2C-. Color and bleach response time is 3.0s and 4.0s, respectively.