TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Components: The carbonate-based additive compound is cyclic carbonate, fluoroethylene carbonate, or compound of structure (I).X = halogen, CN, or NO2.The carbonate-based additive compound is present at 0.1-10, preferably 0.01-5 wt.% based on total amount of electrolyte. The lithium salts are lithium hexafluorophosphide, lithium tetrafluoro phosphide, lithium-tin-hexafluoride, lithium-hexa fluoro arsenide, lithium chlorate, lithium-trifluoromethyl-sulfite, lithium-nitro-trifluoromethyl-sulfoxide, lithium nona-fluoro-butyl-sulfite, lithium aluminum oxide, lithium aluminum chloride, lithium-nitro-fluoromethyl sulfoxide, lithium chloride, or lithium iodide. The lithium salts are used at 0.6-2M. The electrolyte also comprises compound of structure (IV), aromatic hydrocarbon organic solvent of structure (II), swelling-inhibiting additive, organic sulfone-based compound of structure (III) organic solvent with high boiling point, and organic solvent with low boiling point.R = halogen, 1-10C alkyl;R1, R2 = (optionally halogen-substituted) 1-4C prim., sec., or tert. alkyl group, 1-4C alkenyl, 6-14 aryl, 2-4C alkenyl, or 3-6C cycloalkyl; R1 and R2 are bound together to form a cyclic ring;R4 = 1-10C alkyl, 1-10C alkoxy, or 6-10C aryl;n = 0-6;m = 1-5;m+n = at most 6;X = halogen.The organic solvent with high boiling point is gamma-butyrolactone, ethylene carbonate, di propyl carbonate, acid anhydride, N-methyl pyrrolidone, N-methyl acetamide, N-methyl formamide, acetonitrile, dimethyl formamide, sulforane, dimethyl sulfoxide, and/or dimethyl sulfite. The organic solvent with low boiling point is dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, ethylpropyl carbonate, methyl ethyl carbonate, propylene carbonate, and/or butylene carbonate. The aromatic hydrocarbon organic solvent is (fluoro)benzene, (fluoro)toluene, trifluoro toluene, and/or xylene. The sulfone-based compound is vinyl sulfone, methyl sulfone, methyl vinyl sulfone, ethyl vinyl sulfone, phenyl sulfone, phenyl vinyl sulfone, chlorophenyl vinyl sulfone, methyl vinyl sulfone, ethyl vinyl sulfone, phenyl sulfone, phenyl vinyl sulfone, chlorophenyl vinyl sulfone, fluorophenyl vinyl sulfone, benzyl sulfone, tetramethylene sulfone, and/or butadiene sulfone. The sulfone-based compound is present at 0.01-10, preferably 0.01-06 wt.% based on total amount of electrolyte. The compound (IV) is 3-fluoroanisole, 3-chloroanisole, 3-bromoanisole, 4-fluoroanisole, 4-chloroanisole, 4-bromoanisole, 2,4-difluoroanisole, 3,5-difluoroanisole, and/or 3-chloro-5-fluoroanisole. The compound IV is present at 0.01-10, preferably 0.01-6 wt.% based on electrolyte. swelling-inhibiting additive is propane sulfone, bisphenol, dimethyl furan, 1,3-propandiol cyclic sulfate, and/or N-acetyl caprolactam. The positive electrode includes lithium-nickel based or lithium-nickel-manganese based oxide. The negative electrode includes 100% natural graphite. The secondary battery includes lithium ion battery or lithium polymer battery. The ethylene carbonate derivative includes electron-withdrawing groups with high electro negativity. The electrolyte preferably comprises mixed solvent containing mixture of gamma-butyrolactone, ethylene carbonate, ethyl methyl carbonate derivative added at (0.01-10 wt.%) and fluoroethylene carbonate. The secondary battery also comprises separator (6) containing porous film separator interposed between the two electrodes.Preferred Properties: The organic solvent with high boiling point has boiling point of 100-200, preferably 150degreesC.Preferred Methods: The positive electrode is made by mixing positive active material, conductive agent, and binder in solvent to prepare a positive slurry, coating on a current collector, drying and compressing. The negative electrode is made by mixing negative active material, and binder to prepare negative material slurry, coating on current collector, drying, and compressing.