NOVELTY - A lithium-ion electrochemical cell comprises an anode containing an anode active material in electronically conductive contact with an anode current collector; a cathode contains a cathode current collector, a protective conductive coating on the cathode current collector, a cathode active material placed on the top of the protective, and conductive coating cathode active material containing a lithium insertion transition metal oxide, phosphate or sulfate; an ion-permeable membrane; and an electrolyte solution being in ionically conductive contact with the anode and cathode.    USE - In lithium-ion batteries.    ADVANTAGE - The lithium-ion electrochemical cell reduces the corrosion; and exhibits long cycle life of the battery at high temperature.    DETAILED DESCRIPTION - A lithium-ion electrochemical cell comprises an anode containing an anode active material in electronically conductive contact with an anode current collector; a cathode exhibiting an upper charging voltage of 3-5 volts with respect to a Li/Li+ reference electrode, where the cathode contains a cathode current collector, a protective conductive coating on the cathode current collector, a cathode active material placed on the top of the protective, and conductive coating cathode active material containing a lithium insertion transition metal oxide, phosphate or sulfate; an ion-permeable membrane as a separator between the anode and cathode; and an electrolyte solution being in ionically conductive contact with the anode and cathode, where the electrolyte solution contains an additive, a lithium compound (0.1-3 molar), and at least one aprotic polar solvent and/or a polymer. The lithium compound is a compound of formula (Rf1)SO2X-(Li+)Y1(Z1)a. The additive is selected from LiBOB, LiF, LiFOB, LiPF6, LiBF4, LiAsF6, LiClO4, and LiP(F)j(Rf7)k.    Rf1=1-4C perfluoroalkyl radical (optionally interrupted by ether oxygen);    X=C or N;    a=0 or 1;    Z1=CN, SO2Rf2, SO2R, P(O)(OR)2, CO2R, P(O)R2, C(O)Rf3, C(O)R, cycloalkenyl or H;    Y1=Z1 or SO2Rf6;    R=1-6C alkyl (optionally interrupted by ether oxygen, and optionally substituted with aryl);    Rf2 and Rf3=1-4C perfluoroalkyl radicals (optionally interrupted by ether oxygen);    Rf6=-(Rf4SO2N-(Li+)SO2)mRf5;    m=0 or 1;    Rf4=-(C)n(F)2n;    n=1-4;    Rf4=optionally interrupted by ether oxygen;    Rf5=-(C)n(F)2n+1 (optionally interrupted by ether oxygen);    j+k=6;    Rf7=CF3 or (C)2F5.    Provided that    (1) when a is 1 then X is C;    (2) when a is 0 then X is N;    (3) Y1 and Z1 cannot both be H.