Ionic conductivities of cross-linked polymer electrolytes prepared from oligo(ethylene glycol) dimethacrylates

Cross-linked polymer electrolytes are prepared from oligo(ethylene glycol) dimethacrylates (OEGDMA) with different ethylene oxide repeating units in t he presence of lithium perchlorate as a lithium salt, ethylene carbonate-pr opylene carbonate as a mixed plasticizer, and poly(ethylene oxide) as a pol ymer matrix. The ionic conductivities of polymer electrolytes increase with an increasing amount of the ethylene oxide repeating unit in the OEGDMA. C onversely, the glass transition temperatures of the polymer electrolytes de crease with an increasing amount of the unit. The increased ionic conductiv ity can be explained by the sites of the spaces surrounded by the main chai ns and the cross-linking spacers in the polymers. (C) 2000 Elsevier Science S.A. All rights reserved.