HIGHLY CONDUCTING SOLID ELECTROLYTES BASED ON POLY(ETHYLENE OXIDE-CO-PROPYLENE OXIDE)

The conducting properties of solid electrolytes comprising random poly (ethylene oxide-copropylene oxide) (of 84 : 16 monomer units mole rati o) and lithium, sodium, potassium, cesium, and rubidium salts have bee n studied. The systems containing some lithium or sodium salts achieve d conductivity levels as high as 10(-5)-10(-4) S/cm at ambient tempera ture and greater than 10(-3) Slcm at 100 degrees C. However, the syste ms with rubidium and cesium salts exhibit conductivities a few orders of magnitude smaller. DSC studies show that the electrolytes studied a re characterized by a high content of an amorphous phase (95-100%). It is suggested that the copolymer exhibits lower complexing abilities t han that of poly(ethylene oxide), which results in a higher flexibilit y of electrolytes containing small cations and poor dissociation of th e salts having large cations. (C) 1995 John Wiley and Sons, Inc.