Aprotic electrolytes are essential for lithium batteries, electrochromic windows, electrochemical supercapacitors and similar systems. These materials can be also used in the solid-state electrochemical sensors. This paper deals with the basic properties of gel polymer electrolytes based on propylene carbonate immobilised by polymethylmethacrylate (MMA) as a part of their systematic research. Electric conductivity, metal electrodeposition from gels containing cadmium perchlorate and properties of ferrocene/ferricinium redox couple were investigated. (C) 2004 Elsevier B.V. All rights reserved.