Abstract: A composition useful as an electrolyte in a lithium-ion battery comprises at least one C3-C6 carbonate or a lactone, at least one unsaturated cyclic carbonate in a v/v proportion less than 5% of the volume of the other constituents of the composition, lithium hexafluorophosphate (LiPF6) and at least 0.2 mol/l lithium bis(oxalatoborate). A battery using this electrolyte is suitable for operation at temperatures down to about ?50° C.

Abstract: The use of a rechargeable lithium storage cell at a temperature lying in the range 80° C. to 180° C., said cell comprising a cathode, an anode comprising either Li4Ti5O12 or a carbon-containing material capable of inserting lithium, a separator, a non-aqueous solvent, and a lithium slat, wherein: the active material of said cathode is a lithiated metal oxide having the following formula: LiNi1-x-yCoxAl/MnyO2 in which: Al/Mn means Al and/or Mn; 0?x?0.5; 0?y?0.5; the sum x+y being less than 0.66; and wherein the lithium salt is selected from the group consisting of: LiPF6, LiBF4, LiBOB, LiBETI, and mixtures thereof.