|Institution:||Brno University of Technology|
|Keywords:||Gelový polymerní elektrolyt; Specifická vodivost; Methakrylát; Elektrochromní prvek; Propylenkarbonát; Oxid hlinitý; Nanočástice; Redoxní elektrolyt; Lithium; Gel-polymer electrolyte; Ionic conductivity; Methacrylate; Electrochromic device; Propylene carbonate; Aluminium oxide; Nanoparticles; Redox electrolyte; Lithium|
|Full text PDF:||http://hdl.handle.net/11012/9929|
Předkládaná práce se zabývá výzkumem nových materiálů a metod přípravy gelových polymerních elektrolytů (GPE) na bázi methakrylátů, které lze zejména vzhledem k jejich mechanickým vlastnostem s výhodou využít při konstrukci elektrochromních (EC) prvků.; This work deals with the research on the methacrylate based gel polymer electrolytes (GPEs) primarily but not solely designed for use in electrochromic (EC) devices, but also in other Li-ion applications. An EC device comprises an active solar control film whose transmittance in the visible and near IR part of the spectrum can be reversibly modulated by a low DC voltage. The poly(methyl methacrylate) PMMA based redox electrolyte with I3-/I- pair was introduced. The method of in-situ thermal polymerization of the gel was used to prepare a hybrid FTO|WO3|redox GPE|Pt|FTO cell in a vacuum bag. The relationship between the electrolyte composition and the parameters such as change of transmittance, response time and stability was discussed based on results from coupled optoelectrochemical measurements. The hybrid EC cell showed moderate optical modulation (ca 30 % of dT at 634 nm), slow initial state recovery and relatively low coloration efficiency (10.5 cm2/C). On the other hand the switching speeds (< 20s) were observed. The new poly(ethyl methacrylate) PEMA and poly(2-ethoxyethyl methacrylate) PEOEMA based polymer gel electrolytes with entrapped solutions of LiClO4 in propylene carbonate (PC) were prepared by direct, UV initiated polymerization. The electrolytes exhibit good ionic conductivity (up to 1.9 mS/cm at 20 °C) as well as electrochemical stability up to 5.1 V vs. Li/Li+ on gold electrode. The electrolytes were successfully tested as ionic conductors in the electrochromic device FTO/WO3/Li-electrolyte/V2O5/FTO. The transmittance change was found to be ca 53 % of dT at 634 nm. Further the GPEs based on PMMA-PC- LiClO4 or NaClO4 electrolytes were prepared using either the commercial product Superacryl or directly by the heat or UV induced polymerization of a monomer. The nanostructured aluminum oxide added to the latter mentioned systems in various ratios was found to enhance their ionic conductivity.