TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The lithium salt comprises: lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate(V), lithium hexafluoroantimonate, lithium perchlorate, lithium hexachloroplatinate, lithium bis(trifluoromethane)sulfonylimide, lithium tris(trifluoromethanesulfonyl)methide or lithium trifluoromethanesulfonate; lithium borate salts, preferably lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium difluoro-malonato-borate, lithium difluoroglycolatoborate, lithium difluorosalicylatoborate, lithium difluorolactatoborate and/or lithium difluorocatecholatoborate; lithium salts of sulfonylimides, preferably bis(trifluoromethanesulfonyl)imide or bis(pentafluoroethanesulfonyl)imide; and/or lithium tetrafluoro(oxalato)phosphate, preferably lithium hexafluorophosphate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: (I) comprises 1,1,1,3,3-pentafluoro-propan-2-one, 1,1,1,3-tetrafluoro-propan-2-one, 1,1,3,3-tetrafluoro-propan-2-one, 1,1,1-trifluoro-propan-2-one, 1,1,3-trifluoro-propan-2-one, 1,1-difluoro-propan-2-one, 1,3-difluoro-propan-2-one or 1-fluoro-propan-2-one. The solvent comprises: an aprotic solvent comprising propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, acetonitrile, glutaronitrile, adiponitrile, pimelonitrile, gamma-butyrolactone and/or gamma-valerolactone; an ionic liquid comprising bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium-bis(trifluoromethanesulfonyl)imide and/or N-methyl-N-propylpyrrolidinium-bis(trifluoromethanesulfonyl)imide; and/or a polymer electrolyte comprising polyethylene oxide, polyacrylonitrile and/or polymethylmethacrylate. The weight of a mixture of the solvent and (I) in the electrolyte, is 0.1-15 wt.%, preferably 1-5 wt.%, based on the total weight of the mixture containing at least one compound (I). Preferred Definitions:    R1 = CH3, CH2F, CHF2, CF3 (all claimed), H, C2H5, C2H4F, C2H3F2, C2H2F3, C2HF4 and/or C2F5;    R2 = -C(R3)-R4;    R3 = H, CH3, CH2F, CHF2 and/or CF3; and    R4 = H, F, CH3, CH2F, CHF2 and/or CF3.    EXAMPLE - Mixture of propylene carbonate (95 wt.%) and fluoroacetone (5 wt.%) was provided. Then lithium hexafluorophosphate (152 g/l) was dissolved in the mixture to obtain the electrolyte.