TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Electrolyte : Compound (I) has a structure represented by general formula (2).X1 = at least one group selected from groups (a) ;R1, R2 = 1-20C hydrocarbon chains or 1-10 unit oligoether chainsCompound (I) has a structure represented by general formula (3) and a structure represented by general formula (4) in the same molecule. The compound (I) contains the structure represented by (5).X = 1-20C hydrocarbon chains or 1-10 unit oligoether chains ;n = integer greater than 0In the electrolyte, the mole ratio of B/A lies between 0.001 and 10, where A represents the mole number of the structure represented by general formula (1) contained in compound (I), and B represents the mole number of the electrolyte salt.The electrolyte salt is at least one salt selected from MPF6, MBF4, MAsF6, MSbF6, MCF3SO3, MCF3CO2, M2C2F4(SO3)2, MN(CF3SO2)2, MN(C2F6SO2)2, MC(CF3SO2)3, MCnF2n+1SO3, MNasteriskRfOSO2)2 and MOH.M = alkali metal ;n = integer =2 or greater ;Rf = fluoroalkyl groupCompound (I) is produced by condensation reaction of a compound containing a structure represented by general formula (1) and also two or more carbonate ester groups capable of reacting with OH groups, with a compound containing at least one OH group. WIDER DISCLOSURE - A battery comprises positive and negative electrodes and the invented ion-conductive electrolyte placed between them.    EXAMPLE - A polymer having a structure represented by general formula (1), was produced by reacting 1, 4:3, 6-dianhydro-2,5-bis-O-(phenoxycarbonyl)-D- glucitol (97.5 mole%), (CH3COO)2Zn (2.7 mole%) and 1,6-hexanediol at 190 degreesC. The polymer and Li(SO2CF3) were dissolved in acetonitrile, and the resulting solution was coated on a stainless steel plate and on a polytetrafluoroethylene film adhered on a glass, and then both were dried so as to remove the acetonitrile. The obtained electrolyte film had an ion-conductivity of 0.10 mS/cm, a Li+ transport number of 0.30, and a B/A ratio of 0.2.