Composite polymeric electrolytes from the PEODME-LiClO4-SiO2 system

It is shown that the addition of fumed silica to polymer electrolytes results in the formation of gel-like polymer materials. Despite the quasi-solid structure of these composite systems, compared to the liquid base poly(ethylene oxide) dimethyl ether (PEODME)−LiClO4 electrolyte, an increase in conductivity is observed for several salt concentrations of composite systems compared to that of the PEODME−LiClO4 electrolytes. For other salt concentrations, the conductivities of the composite systems are slightly higher or at least comparable to that measured for the unmodified electrolyte. At the lowest salt concentrations (e.g., 10-5−10-4 mol/kg PEODME), the conductivities of the PEODME−LiClO4 electrolyte are higher. This increase in conductivity is related to the reduction in the fraction of ion pairs as revealed by FT-IR experiments and Fuoss−Kraus-type analyses of the salt concentration dependence of the ionic conductivity.