Sintese e caracterizacao de polieteres electroliticos. Sua aplicabilidade em sistemas de energia

Abstract

PEO-LiCF_3SO_3 polymer electrolyte films have been prepared by hot mechanical mixing of the components. The conductivity behaviour of these films has also been investigated. Another polymeric system that has been studied is an interpenetrating polymer network (IPN):electrolyte. The main objective was to assess their applicability to solid state batteries. For the PEO-LiCF_3SO_3 the best processing temperature was between 120 and 140degC, at a pressure of 246.8 Kg/cm"2. Polymer films of thickness varying between 50 and 200 #mu#m were obtained.Conductivities as high as 1.35x10"-"4 Scm"-"1, at room temperature, were measured for the molar relation polymer/salt equal to 22. It was shown, by thermal analysis, that the films behave as those prepared by solvent casting. The interpenetrating polymer network electrolytes have been prepared by solvent cast method, by admixing 4 - 4'- isopropylidenediphenol epichlorohydrin resin, diethylenetriamine (curing agent), polyethyleneglycol (MW 400) and magnesium perchlorate, in acetonitrile (5% wt. solutions), following the acetonitrile evaporation. The ionic conductivity (by ac impedance), the electrochemical window (by dc voltammetry), and other polymer parameters have been determined. Moreover, the interfacial impedance of the magnesium/polymer electrolyte systems has been studied. Although the conductivity of the IPN is quite good, 0.34x10"-"4S cm"-"1, at room temperature, as well as other characteristics of the IPN, the Mg/PEG-Mg(ClO_4)_2:IPN system seems not to be appropriate for battery application due to its high interfacial impedanceAvailable from Fundacao para a Ciencia e a Tecnologia, Servico de Informacao e Documentacao, Av. D. Carlos I, 126, 1200 Lisboa / FCT - Fundação para o Ciência e a TecnologiaSIGLEPTPortuga