The influence of inert oxide fillers on poly(ethylene oxide) and amorphouspoly(ethylene oxide) based polymer electrolytes

An FT-Raman study was performed on lithium salt/polymer/nanosized inert oxi de filler (SiO2, Al2O3) systems. Molecular spectroscopy suggests that there is little effect of the filler particles on the "free" anion/ion-pair/ hig her aggregate equilibria. Raman line widths indicate enhanced anion disorde r when a small amount of filler is introduced. Similarly, DSC measurement i ndicates a reduction of crystallinity. By contrast, fully amorphous polymer samples display broader Raman line widths and higher glass transition temp eratures as the filler concentration is increased, with concomitant lower i on conductivity. The influence of the fillers differs in proportion to the extent of crystallinity of the polymer-salt complex, but within our experim ental range the particle size or composition of the filler has little influ ence on ionic conductivity.