TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Cell: In the electrochemical cell, the stabilized lithium metal oxide material in its initial discharged state is represented by formula: xLiMO2.(1-x)Li2M'O3, where 0 less than or equal to x less than or equal to 1.M=ions having an average oxidation state of 3 with at least one ion being Mn; andM'=ions having an oxidation state of 4 and selected from Mn, Ti, and Zr.The stabilized lithium metal oxide material in its initial discharged state is represented by formula: xLiMO2.(1-x)Li2M'O3, where 0 less than or equal to x less than or equal to 1.M=ions having an average oxidation state of 3 with at least one ion being Ni; andM'=ions having an average oxidation state of 4 with at least one ion being Mn.The lithium salt is selected from lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium hexafluoroantimonate (LiSbF6), lithium hexafluoroarsenate (LiAsF6), lithium perchlorate (LiClO4), lithium trifluoromethanesulfonate (LiCF3SO3), LiC4F9SO3, LiAlO4, lithium tetrachloroaluminate (LiAlCl4), lithium chloride (LiCl), lithium iodide (LiI), and combinations, where the lithium salt is LiPF6. The electrolyte ingredients further comprises a high temperature performance additive, preferably bis(trifluoromethanesulfonyl)imide. Alternatively, the electrochemical cell comprises: an electrode comprising a material represented by formula LiMO2, where M includes one or more transition metal ions; and an electrolyte formed from ingredients comprising a solvent, a lithium salt, and a sultone; and a negative electrode. The material is represented by formula LiMO2 is lithium manganese dioxide (LiMnO2).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Cell: In the electrochemical cell, the sultone is represented by Formula (1).R1, R2, and R3=H, halo, an alkyl group having 1-3 carbon atoms, and a halogenated alkyl group having 1-3 carbon atoms.The sultone is selected from 1,3-propane sultone, 1-methyl-1,3-propane sultone, 2-methyl-1,3-propane sultone, 3-methyl-1,3-propane sultone, 1-ethyl-1,3-propane sultone, 2-ethyl-1,3-propane sultone, 3-ethyl-1,3-propane sultone, 1,2-dimethyl-1,3-propane sultone, 1,3-dimethyl-1,3-propane sultone, 2,3-dimethyl-1,3-propane sultone, 1-methyl-2-ethyl-1,3-propane sultone, 1-methyl-3-ethyl-1,3-propane sultone, 2-methyl-3-ethyl-1,3-propane sultone, 1-ethyl-2-methyl-1,3-propane sultone, 1-ethyl-3-methyl-1,3-propane sultone, 2-ethyl-3-methyl-1,3-propane sultone, 1-fluoromethyl-1,3-propane sultone, 2-fluoromethyl-1,3-propane sultone, 3-fluoromethyl-1,3-propane sultone, 1-trifluoromethyl-1,3-propane sultone, 2-trifluoromethyl-1,3-propane sultone, 3-trifluoromethyl-1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1,2-difluoro-1,3-propane sultone, 1,3-difluoro-1,3-propane sultone, 2,3-difluoro-1,3-propane sultone, and combinations. The sultone is 1,3-propane sultone. The electrolyte sultone concentration is 0.05-2 wt.%, based on the total weight of the electrolyte. The solvent is selected from dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, and combinations. The solvent comprises ethylene carbonate and ethyl methyl carbonate. EXAMPLE - No suitable example given.