NOVELTY - A phase transition lithium-ion electrolyte comprises lithium-salt and organic compound including acid amide functional group. The lithium-salt is lithium bis(2-hydroxy-3-chloro-5-methyl cyclohexane carboxy)borate, lithium bis(2-hydroxy-3,6-dichloro-5-methyl cyclohexane carboxy)borate, lithium bis(2-hydroxy cyclohexane carboxy)borate, lithium bis(2-hydroxy-3-methyl cyclohexane carboxy)borate, lithium bis(1,1,2,2-tetratrifluoromethyl-1,3-diolato)borate, lithium bis(pyridine-2,3-diolato)borate and lithium bis(benzene-2,3-diolato)phosphate.    USE - Phase transition lithium-ion electrolyte is used for rechargeable lithium battery (claimed).    ADVANTAGE - The phase transition lithium-ion electrolyte has high conductivity, thermal stability and chemical stability.    DETAILED DESCRIPTION - A phase transition lithium-ion electrolyte comprises lithium-salt and organic compound including acid amide functional group. The lithium-salt is lithium bis(2-hydroxy-3-chloro-5-methyl cyclohexane carboxy)borate, lithium bis(2-hydroxy-3,6-dichloro-5-methyl cyclohexane carboxy)borate, lithium bis(2-hydroxy cyclohexane carboxy)borate, lithium bis(2-hydroxy-3-methyl cyclohexane carboxy)borate, lithium bis(1,1,2,2-tetratrifluoromethyl-1,3-diolato)borate, lithium bis(pyridine-2,3-diolato)borate, lithium bis(benzene-2,3-diolato)phosphate, lithium bis(4-methyl benzene-1,2-diolato)phosphate, lithium bis(3-fluoro benzene-1,2-diolato)phosphate, lithium di-4-nitrophenyl sulfonamide, lithium bis(catecholato)borate, lithium bis(3,3-difluorocatecholato)borate, lithium bis(decahydronaphthalene-2,3-diolato)borate, lithium bis(3,4,5,6-tetrafluoro-3,4,5,6-tetrahydrocatecholato)borate, lithium bis(1,1'-bi(cyclohexyl)-2,2'-diolato)borate, lithium bis(dioxalato)borate, lithium 1,1,2,2,3,3,4,4,4-nonafluoro-N-((trifluoromethyl)sulfonyl)butane-1-sulfonamide and/or lithium bis(malanato)borate. An INDEPENDENT CLAIM is included for preparation of electrolyte, which involves mixing the lithium-salt with the organic compound, heating the mixture (A) under dry condition and cooling obtained transparent liquid so as to obtain the electrolyte.