Gel polymer electrolytes (GPE) composed of poly(ethylene-co-methyl acrylate) copolymer, LiBF4-EC/EMC/PC, and silanized fumed silica are prepared. The ionic conductivity reaches 5.8 X 10(-4) S cm(-1) in the GPE containing 22% poly(ethylene-co-methyl acrylate), 65% LiBF4-EC/EMC/PC and 13% silanized fumed silica at room temperature. GPEs are free-standing films and are used to prepare thin films for rechargeable lithium-ion polymer cells. Lithium-ion polymer cells, which consist of mesophase carbon fibre anode, poly(ethylene-co-methyl acrylate)-based GPE and LiCoO2 cathode, are assembled, and their charge-discharge cycling characteristics are investigated. (C) 2000 Elsevier Science S.A. All rights reserved.