Ionic conductance of polymeric electrolytes containing lithium salts mixed with rare earth salts

Polymeric ion conductors consisting of poly(ethylene oxide)-grafted poly(methylmethacrylate) (PEO–PMMA) matrices that dissolve lithium salts and rare earth salts have been prepared by photo-induced radical polymerization of methacrylate monomers with a linear polyether (PEGDE). The ionic structure and conductance behaviour of the resulting electrolyte systems were investigated as a function of the electrolyte composition. Polymeric electrolytes containing lithium salts with rare earth cations showed higher ionic conductivity than that containing lithium salts only. The conductance behaviour of the mixed salt system is discussed from the experimental results of thermal analysis, Raman spectroscopy, transport number measurements and 7Li NMR.