Composite polymer electrolyte based on (PEO)6:NaPO3 dispersed with BaTiO3

BACKGROUND: Polymer electrolytes have attracted considerable attention as regards portable solid-state electrochemical device applications. The present investigation is focused on the characterization of a new Na+ ion conducting polymer electrolyte (PEO)(6):NaPO3 dispersed with 3-10 wt% BaTiO3 (0.7 mu m) fillers. The composite polymer electrolytes (CPEs) were prepared by a solution-casting method and characterized using various physical measurement techniques. RESULTS: Differential scanning calorimetry results indicate a maximum reduction in the degree of crystallinity of the polymer from 62.6% for uncomplexed poly(ethylene oxide) (PEO) to 27.6% for the CPE with 6 wt% BaTiO3. This substantiates an enhancement in the amorphous phase of the polymer inferred from X-ray diffraction and optical micrographs. The CPE dispersed with 6 wt% BaTiO3 is found to be the best composition exhibiting a maximum ionic conductivity of 1.2 x 10(-6) S cm(-1) at 345 K with cationic transport number (tNa(+)) of 0.33. CONCLUSIONS: An enhancement in the ionic conductivity of about two orders of magnitude is achieved for the composite electrolytes when compared to filler-free solid polymer electrolyte. Correlation of the temperature-dependent conductivity, activation energy for ion migration and transport number enables an understanding of the role played by the fillers in conduction characteristics of the CPEs. (c) 2007 Society of Chemical Industry.