HIGHLY CONDUCTIVE SOLID POLYMER ELECTROLYTES PREPARED BY BLENDING HIGH-MOLECULAR-WEIGHT POLY(ETHYLENE OXIDE), POLY(2-VINYLPYRIDINE OR 4-VINYLPYRIDINE), AND LITHIUM PERCHLORATE

Highly ionic conductive solid polymer electrolytes have been prepared by blending poly(ethylene oxide) (MW 600 000) and poly(2-vinylpyridine ) (MW 200 000) or poly(4-vinylpyridine) (MW 50 000) and LiClO4. All bl ends were prepared by the solution blending process. Several different blend compositions have been studied and optimum compositions require d for preparing solid polymer electrolytes have been determined. The p oly(ethyleneoxide) (85% by weight)/poly(2-vinylpyridine) (15% by weigh t)/LiClO4 blend at an ethylene oxide/Li+ mole ratio of 10 exhibits an ionic conductivity value of 1.0 x 10(-5) S cm-1 at 25-degrees-C and is an elastomeric material with dimensional stability. Furthermore, this blend exhibits ionic conductivities >3.0 x 10(-6) S cm-1 at 25-degree s-C over a wide salt concentration range. Several other blends prepare d are also elastomeric materials with ionic conductivities approximate ly 5.0 x 10(-6) S cm-1, e.g. poly(ethylene oxide) (85% by weight)/poly (2-vinylpyridine) (15% by weight)/LiClO4 at an ethylene oxide to Li+ m ole ratio of 6 exhibits a value of 7.0 x 10(-6) S cm-1 at 30-degrees-C . Studies indicate that the LiClO4 salt compatibilizes the poly(ethyle ne oxide) and the poly(2-vinylpyridine) by the simultaneous interactio n of the Li+ with the oxygens of the PEO and nitrogen of the pyridyl u nits. Scanning electron microscopy (SEM) on the internal structure of the blends shows the presence of a two phase microstructure, most like ly, stabilized by the emulsifying effect of LiClO4.