Preparation Of Polymer Electrolytes And Their Applications In Electrochromic Devices

The rapid development of economy and the increasing progress of science and technology have brought us not only a better life but also huge energy consumption.Electrochromic materials,as a kind of energy-saving and environmental-friendly material,can reduce energy consumption,complying with the trend of the development.The research of electrolytes with better performance has become a hit in order to realize the discoloration and industrialization of electrochromic devices.In this paper,polymer electrolytes with PVB,agar and PMMA served as matrix were prepared by different methods,and the effects of electrolyte salt content and doped inorganic filler on the ionic conductivity of polymer electrolyte were studied.The group with the highest ionic conductivity was selected and applied to electrochromic devices,and the performance of each device was studied.The main research results obtained in this paper are as follows:?1?PVB was dissolved in anhydrous ethanol,lithium trifluoromethane sulfoimide?LiTFSI?was added as lithium salt,and silicon dioxide?SiO₂?was used as inorganic filler to prepare a sticky polymer solution.PVB-based gel polymer electrolyte was prepared directly on transparent conductive glass by spin coating method.The results showed that,within a certain range,the ionic conductivity of electrolyte increased with the increase of lithium content,and the ionic conductivity of PVB-based gel polymer electrolyte containing0.3 mol·L^-1 LiTFSI at room temperature is 4.2×10^-5 S·cm^-1.The ionic conductivity of electrolyte can be improved by adding inorganic filler.The ionic conductivity of electrolyte containing 0.3 mol·L^-1 LiTFSI and 0.2 g SiO₂ at room temperature is 9.8×10^-5 S·cm^-1.The PVB-based gel polymer electrolyte was respectively spun onto an indium tin oxide?ITO?glass surface which deposited with Prussian blue?PB?film and a blank ITO glass conductive surface,and the two pieces of ITO glass were pressed and assembled into an electrochromic device.The obtained electrochromic device at 575 nm has a modulation amplitude of 45.2%,and the response time of coloring and fading are respectively 23.4 s and 22.1 s.?2?Agar,LiTFSI and propylene carbonate?PC?were dissolved in deionized water with heating,and the agar-based gel polymer electrolyte was obtained after cooling.The results showed that,within a certain range,the ionic conductivity of the electrolyte increased with the increase of lithium content,and the ionic conductivity of the electrolyte containing 0.12 mol·L^-1 LiTFSI at room temperature is 6.7×10^-3 S·cm^-1.The prepared electrolyte solution was injected into the preassembled device,and the electrochromic device with agar-based gel polymer electrolyte served as the electrolyte layer was directly obtained after cooling.At 595 nm,the modulation amplitude of the transmittance of the device can reach 46.8%,and the response time of coloring and fading are respectively 24.7s and 22.4 s.?3?PMMA was dissolved in PC and LiTFSI and SiO₂ were added to prepare PMMA quasi gel polymer electrolyte.The results showed that,within a certain range,the ionic conductivity of electrolyte increased with the increase of lithium content,and the ionic conductivity of electrolyte containing 0.3 mol·L^-1 LiTFSI at room temperature is 4×10^-4S·cm^-1.The ionic conductivity of electrolyte containing 0.3 mol·L^-1 LiTFSI and 0.2 g SiO₂ is5.9×10^-4 S·cm^-1,indicating that the ionic conductivity of electrolyte was improved after the addition of inorganic filler.The prepared PMMA quasi gel polymer electrolyte was coated on an ITO glass which deposited with PB film and bonded with a blank ITO glass to form an electrochromic device.The modulation amplitude of the transmittance of the device at636 nm is up to 49.9%,and the response time of coloring and fading are respectively 5.2 s and 14.2 s.The prepared PMMA quasi gel polymer electrolyte was coated on an FTO glass which deposited with polypyrrole film and bonded with a blank FTO glass to form an electrochromic device at the same time.The modulation amplitude of the transmittance of the device at 772 nm is up to 49.1%,and the response time of coloring and fading are respectively 7.3 s and 14.5 s.