Lithium-ion conducting composite polymer electrolytes (CPE),(PEO)(8)-LiCF3SO3 (PEO = polyethylene oxide) dispersed with a glass-ceramic, Li-1.4[Al0.4Ge1.6(PO4)(3)] as a filler have been prepared as films and their thermal, mechanical, electrical and electrochemical properties have been studied. The glass transition temperature increases with filler addition reaches a maximum value of -39 degreesC for x = 7.5 wt.%, and then decreases. Enhancement in the electrochemical stability of the films is noted; a maximum working voltage of 3.75 V is found at x = 10 wt.%. Addition of filler decreases the ionic conductivity for x = 7.5 wt.%, a = 1.6 x 10(-7) S cm(-1) which is a factor three lower than that for the PS complex. The E-a and log(10)(sigma(0)) values of the composite polymer electrolytes consistently decrease with increasing x. The mechanical properties are enhanced with filler addition, a maximum tensile strength of 22.8 MPa, is obtained at x = 7.5-10 wt.%, a value which is three times higher than that for the PS complex. (C) 2003 Elsevier Science B.V. All rights reserved.