TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - The crosslinkable compound contains 1 or more kinds of compounds with at least 1 crosslinkable functional group, particularly with 1 or more other bonds at the free terminal, such as an ester compound, especially 1 or more of mono-, di- or triester compounds, e.g. of formula (XVI) or (XVII) or (XVIII). (XVI)R1, R2, R3 = H or alkylx and y being integers, x at least and y at least 0 or x at least 0 and y at least 1.(XVII)R4, R5, R6 = H or alkylX and Y being integers, X at least 1 and Y at least 0 or X at least 0 and Y at least 1.(XVIII)R7, R8, R9 = H or alkylp and q being integers, p at least 1 and q at least 0 or p at least 0 and q at least 1.Weight ratio of the monoester compound/the diester compound is 0-5. Such crosslinkable compound can be a copolymer containing structural units of formula (XIX) or (XX). (XIX)R10 = alkyl, alkenyl, cycloalkyl, aryl, aralkyl or tetrahydropyranylh = integer, at most 12.(XX)R11 = function group with active hydrogen group or/and unsaturated double bond, or functional group containing active hydrogen group or/and unsaturated double bond, together with at least H, alkyl, alkenyl, cycloalkyl or/and alkyl.The ratio of mole number of electrolyte/that of crosslinkable compound with ether bond is not more than 0.0001. Preferably, the polymer contains a siloxane derivative of formula (XXI). (XXI) where D = -Si(CH3)2-O-; D' =a = 0-100b = 1-100m = 0-100n = 0-100R12 = H or alkyl, but when b not less than 1, b-number of D' can be the same or different, and R12 in D' contains H atoms which can be optionally substituted by halogens.The ratio of mole number of the electrolyte/that of ether bond units in the siloxane derivative is 0.0001-5. Amount of the crosslinkable compound in the composition is 10-10,000 pts.wt., with respect to 100 pts.wt. the siloxane derivative. such siloxane derivative has an average molecular weight of not more than 100,000. The crosslinkabe compound in the electrolyte is particularly an ester compound, with crosslinking groups, which can especially be a crosslinking group-containing diester compound of formula (XXII) or monoester (XXIII) or triester (XXIV) or copolymer (XXV), while the siloxane derivative (XXVII) is used (all as already defined for the corresponding compounds).    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - The electrolyte salt is particularly a lithium salt.    TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Electrolyte Production: Crosslinking is by irradiation with ultraviolet (UV) light, electron beam, X-ray, gamma-ray, microwave or high-frequency radiation, or by heating the crosslinkable compound, particularly by mixing the crosslinkable compound with the polymer first before crosslinking with the electrolyte salt added during the process. Preferred Cells: The cell comprises a positive electrode, negative electrode and the thus made electrolyte obtained from crosslinkable compounds such as those of diester (XXVIII), monoester (XXIX), triester (XXX) and copolymer (XXXI), together with siloxane derivative (XXXII), all as defined above for the corresponding substances, and electrolyte salt. EXAMPLE - A siloxane derivative of formula (IX) (structure below; 1 pt.wt.) dissolved in acetonitrile (50 pts.wt.) was mixed with 1 mol./kg lithium bis(trifluoromethylsulfonyl)imide, polyethylene dimethacrylate of formula (X) (2 pts.wt.) and methoxypolyethylene glycol monomethacrylate of formula (XI) (2 pts.wt.). Then acetonitrile (15 pts.wt.) was removed, and 2,2-dimethoxy-2,2'-phenylacetophenone initiator (0.05 pt.wt.) was added and applied to a substrate for polymerization by irradiation with UV light at 6 mW/cm for 20 min t give a 100-mum thick electrolyte after drying for 6 hrs. Properties of the electrolyte: ion conductivity = 0.15 mS.cm. (IX) (X) (XI)