(EP856538-A1)      A solid polyelectrolyte is made by mixing: (1) a crosslinked polyether copolymer of number-average molecular weight (Mn) of 10000-2,000,000 comprising 1-99 mol.% of a monomer (A) that gives repeating units of formula (I), 99-1 mol.% of a monomer (B) that gives repeating units of formula (II), and 0-15 mol.% of a monomer (C) containing 1 epoxy group and at least 1 reactive functional group; (2) an electrolyte salt compound; and (3) an aprotic organic solvent, or a plasticiser consisting of a derivative or a metal salt of a linear or branched polyalkylene glycol with a number-average molecular weight (Mw) of 200-5000 or a metal salt of the derivative. In (I): R1 = 1-12C alkyl, 2-8C alkenyl, 3-8C cycloalkyl, 6-14C aryl, 7-12C aralkyl or tetrahydropyranyl; and n = 1-12.    USE -   The solid polyelectrolyte may be used in combination with an anode of a lithium metal and a cathode of lithium cobaltate to make a rechargeable battery, which can also be applied in large-volume capacitors and display devices e.g. in electrochromic display and other electronic equipment.    ADVANTAGE -   The solid polyelectrolyte has ion conductivity improved over the prior-art products, and also has good workability, mouldability and mechanical strength.    (JP10510574-X)      A solid polyelectrolyte is made by mixing: (1) a crosslinked polyether copolymer of number-average molecular weight (Mn) of 10000-2,000,000 comprising 1-99 mol.% of a monomer (A) that gives repeating units of formula (I), 99-1 mol.% of a monomer (B) that gives repeating units of formula (II), and 0-15 mol.% of a monomer (C) containing 1 epoxy group and at least 1 reactive functional group; (2) an electrolyte salt compound; and (3) an aprotic organic solvent, or a plasticiser consisting of a derivative or a metal salt of a linear or branched polyalkylene glycol with a number-average molecular weight (Mw) of 200-5000 or a metal salt of the derivative. In (I): R1 = 1-12C alkyl, 2-8C alkenyl, 3-8C cycloalkyl, 6-14C aryl, 7-12C aralkyl or tetrahydropyranyl; and n = 1-12.    USE -   The solid polyelectrolyte may be used in combination with an anode of a lithium metal and a cathode of lithium cobaltate to make a rechargeable battery, which can also be applied in large-volume capacitors and display devices e.g. in electrochromic display and other electronic equipment.    ADVANTAGE -   The solid polyelectrolyte has ion conductivity improved over the prior-art products, and also has good workability, mouldability and mechanical strength.    (US6162563-A)      A solid polyelectrolyte is made by mixing: (1) a crosslinked polyether copolymer of number-average molecular weight (Mn) of 10000-2,000,000 comprising 1-99 mol.% of a monomer (A) that gives repeating units of formula (I), 99-1 mol.% of a monomer (B) that gives repeating units of formula (II), and 0-15 mol.% of a monomer (C) containing 1 epoxy group and at least 1 reactive functional group; (2) an electrolyte salt compound; and (3) an aprotic organic solvent, or a plasticiser consisting of a derivative or a metal salt of a linear or branched polyalkylene glycol with a number-average molecular weight (Mw) of 200-5000 or a metal salt of the derivative. In (I): R1 = 1-12C alkyl, 2-8C alkenyl, 3-8C cycloalkyl, 6-14C aryl, 7-12C aralkyl or tetrahydropyranyl; and n = 1-12.    USE -   The solid polyelectrolyte may be used in combination with an anode of a lithium metal and a cathode of lithium cobaltate to make a rechargeable battery, which can also be applied in large-volume capacitors and display devices e.g. in electrochromic display and other electronic equipment.    ADVANTAGE -   The solid polyelectrolyte has ion conductivity improved over the prior-art products, and also has good workability, mouldability and mechanical strength.