IONIC-CONDUCTIVITY OF POLYMER GEL ELECTROLYTES BASED ON POLY(POLYETHYLENE GLYCOL DIMETHACRYLATE)

Gel electrolytes have been prepared by thermal polymerization of poly( polyethylene glycol dimethacrylate) (P(PEGD)) in the presence of propy lene carbonate (PC) and alkali metal salts, such as LiClO4, LICF(3)SO( 3) and LiBF4. The conductivity was studied by means of impedance spect roscopy, and it is found that the temperature dependence of conductivi ties follow a Arrhenius relationship when the molar percentage of PC i s higher than 75% or LiClO4 concentration is lower than 0.9 mol/l. How ever, when LiCF3SO3 or LiBF4 is used instead of LiClO4 as the salt, th e situation is different. For LICF(3)SO(3), the Arrhenius relationship almost holds true for all the salt concentrations studied; while for LiBF4, the Arrhenius equation hardly fits for any salt concentration. The dependence of activation energy on salt concentration is also exam ined, both for LiClO4 and LiCF3SO3, the values of E(a) tend to reach a minimum value with increasing salt concentration. Copyright (C) 1996 Elsevier Science Ltd.