Lithium ion conduction in PEO-salt electrolytes gelled with PAN

Hybrid solid electrolyte films consisting of poly(ethylene oxide) (PEO), Li ClO4, a mixture of ethylene carbonate (EC) and gamma-butyrolactone (BL) and poly(acrylonitrile) (PAN) were examined in order to obtain the best compro mise between high conductivity, homogeneity and dimensional stability. Meas urements of electrical conductivity and differential scanning calorimetry h ave been carried out. When the ratio of LiClO4/(EC/BL) is large, the electr olyte films are completely amorphous at room temperature and in the other c ases, they are partially crystalline. The materials having higher EC/BL con tent are more likely to be a gel-electrolyte than a plasticized PEG-salt el ectrolyte. The Li+ ions in these films seem to migrate primarily through th e solvent domains as in the gel-electrolytes. The highest room temperature conductivity of 2.0 x 10(-3) S cm(-1) is found for a film of 31PEO-9LiClO(4 )-50EC/BL-10PAN. This film has a similar conductivity value as compared wit h PAN-based gel electrolytes, but with a better dimensional stability. (C) 1998 Published by Elsevier Science B.V. All rights reserved.