Engineering polymer electrolytes with enhanced ionic conduction

This paper describes our strategies to engineer amorphous polymer-salt comp lexes and investigate their electrical behavior. In the first approach, sem icrystalline polymer polyoxyethylene (POE) was plasticised using amorphous polyoxypropyleneglycol (POPG) in the presence of sodium salts. In the secon d approach. amorphous polymers, poly(bis(methoxyethoxyethoxy phosphazene)) (MEEP) and polysiloxane, were used to synthesise electrolytes. These were c omplexed with sodium salts and a small amount of polyoxyethylene. The natur e of each complex was ascertained from optical microscopy, X-ray diffractio n (XRD) and Differential Scanning Calorimetry (DSC) in these systems. The p olymer-salt complexes, in the first approach, revealed a well-defined glass formation region in which all the compositions were amorphous and showed u nusually high ionic conductivity similar to 10(-4) (Omega cm)(-1) at ambien t temperature. The electrolytes in the second approach showed a maximum con ductivity of similar to 10(-5) (Omega cm)(-1). However, truly amorphous com positions could not he obtained. The first approach of engineering reductio n in crystalline phases appeared more effective in enhancing ionic conducti vity. (C) 2000 Elsevier Science B.V. All rights reserved.