Gel polymer electrolytes (GPEs) composed of porous methyl methacrylate-styrene copolymer membrane and electrolyte solution were prepared. The electrochemical characteristics of these polymer electrolytes were investigated in terms of copolymer composition and content of liquid electrolyte. The ionic conductivity reached 1.0 x 10(-3) S/cm in the gel polymer electrolyte prepared with porous methyl methacrylate-styrene copolymer membrane of which methyl methacrylate composition is 77 mol%. This system showed good mechanical properties and a sufficient electrochemical stability to allow operation in the rechargeable lithium-ion polymer batteries (LIPBs). (C) 2003 Elsevier Science B.V. All rights reserved.