TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Electrolyte: The electrolyte is lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroantimonate, lithium hexafluoroarsenate, lithium perchlorate, lithium trifluoromethane sulfonate, lithium perfluorobutane sulfonate, lithium aluminate, lithium aluminum chloride, lithium chloride, lithium iodide and/or lithium compound (LiN(CxF2x+1SO2)(CyF2y+1SO2)), preferably lithium hexafluoro phosphate, where x and y are natural numbers.Preferred Composition: The volume ratio of high dielectric constant solvent and low viscosity solvent is 15:85-7:93. The concentration of electrolyte in the electrolyte liquid is less than 1 mol/l, preferably 0.15-0.6 mol/l.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The electrolyte liquid further comprises vinylene carbonate (0.1 wt.% or more). SPECIFIC COMPOUNDS - The high dielectric constant solvent is ethylene carbonate, propylene carbonate, butylene carbonate, gamma-butyrolactone, gamma-valerolactone, acetonitrile, (3-methyl) sulfolane, dimethyl sulfoxide, N,N-dimethyl formamide, N-methyl oxazolidinone and/or N,N-dimethyl acetamide, preferably ethylene carbonate. The low viscosity solvent is dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), dimethoxymethane, 1,2-dimethoxy ethane, tetrahydrofuran, 2-methyl tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, methyl formate, methyl acetate and/or methyl propinate, preferably DMC, DEC and/or EMC.    EXAMPLE - Ethylene carbonate and dimethyl carbonate were mixed in a molar ratio of 6:94 and dissolved in lithium hexafluoro phosphate to obtain an electrolyte liquid comprising 1 mol/l of electrolyte. Graphite (in wt.%) (95) and binder were mixed in NMP. A cathode active material was applied on a surface of copper foil which was used as a collector. The coating film was dried at 80 degrees C for 1 hour and molded. Further the film was dried at 120 degrees C and 0.01-1 atm for 12 hours to obtain a cathode. The anode active material was applied on a surface of aluminum foil which was used as collector and dried at 80 degrees C for 1 hour. The film was molded and heat-dried for 12 hours at 120 degrees C to obtain an anode. A separator made of polypropylene was pinched between anode and cathode and stored in stainless steel can. The electrolyte liquid was sealed in the can to produce secondary battery. The time deterioration ratio was decreased by using the electrolyte liquid.