Theory of ionic conduction in organic solvents and gel electrolytes:: application to the system DG/LiCF3SO3 and diacrylate/DG/LiCF3SO3

Gelified electrolytes have been realized by the photopolymerization of tetraethylene glycol diacrylate (TEG) or 1,3-butanediol diacrylate (BDD). The plasticizer is 2-methoxyethylether (DG) and the conductivity is obtained by the addition of lithium trifluoromethane sulfonate (LiTF). As carboxylate groups of BDD have less solvating power for Li+ ions than the ether groups of DG, the conductivity of the BDD/DG gel is dependent on the conductivity of the interstitial liquid phase only. In TEG/DG gel electrolytes, a competitive solvation for Li+ ions exists between the ether sites of TEG and DG, leading to a decrease of ionic mobilities and conductivities. A dynamical theoretical model is proposed to discuss the experimental results. (C) 2001 Elsevier Science Ltd. All rights reserved.