NOVELTY - A lithium (Li) or Li-ion electrochemical cell comprises an ion-permeable membrane as a separator between a cathode and an anode, and an electrolyte solution in ionically conductive contact with anode and cathode. The cathode contains a Li insertion transition metal oxide, phosphate or sulfate. The electrolyte solution comprises an aprotic polar solvent or a polymer and a Li compound.    USE - Used as a lithium or lithium-ion cell.    ADVANTAGE - The lithium or lithium ion cell exhibits improved retention capacity at high discharge rates and improved life span with improved thermal stability. The cell provides improved power and the graphite sheet provides chemical, thermal, tensile and electrical properties with improved mechanical properties of flexibility, compatibility, conformability, flexural toughness and resilience.    DETAILED DESCRIPTION - A Li or Li-ion electrochemical cell comprises an ion-permeable membrane as a separator between a cathode and an anode, and an electrolyte solution in ionically conductive contact with anode and cathode. The anode contains an anode active material (AAM) and an anode current collector in electronically conductive contact with the anode. The cathode exhibits an upper charging voltage of 3-5 V with respect to a Li/Li+ reference electrode and comprises a Li insertion transition metal oxide (LMO), phosphate or sulfate in electronically conductive contact with a cathode current collector comprising graphite. The cathode current collector has a thickness of less than 250 micrometers and graphite has a bulk density of 0.08-2.25 g/cm3 and an electrical conductivity of 500 Siemens/cm. The electronically conductive contact is a resistance of less than 50 OMEGA-cm2. The electrolyte solution comprises an aprotic polar solvent or a polymer and a Li compound of formula: Rf1SO2X-(Li+)YZa, in a molar concentration of 0.2-3.    X = C or N;    a = 0 or 1;    Rf1-Rf3 = 1-4C perfluoroalkyl radicals optionally substituted with ether oxygen(s);    R = 1-6C alkyl optionally substituted with ether oxygen(s) or aryl group optionally further substituted;    Rf6 = radical of formula -(Rf4SO2N-(Li+)SO2)mRf5 optionally substituted with ether oxygen(s);    m = 0 or 1;    Rf4 = -CnF2n-;    Rf5 = -CnF2n+1; and    n = 1-4;    provided that when a is 1, X is C and Y and Z are electron-withdrawing groups from CN, SO2Rf2, SO2R, P(O)(OR)2, CO2R, P(O)R2, C(O)Rf3, C(O)R, cycloalkenyl group and H (but not both H); and when a is 0, X is N and Y is an electron-withdrawing group of formula -SO2Rf6.    An INDEPENDENT CLAIM is included for formation of electrochemical cell. A melt processable composition is formed by combining a polymer (I), a mixture of polar aprotic liquid(s) and a Li compound in a vessel with a mixer. The composition is mixed until it is plastically formable. A sheet is formed from the composition by applying heat and/or pressure. The sheet is layered with a graphite current collector sheet, an ion-permeable separator sheet, anode sheet having AAM and polymer (II), and anode current collector sheet. The layered sheets are consolidated such that the layers are in electrically and/or ionically conductive contact to form an electrochemical cell.    DESCRIPTION OF DRAWING(S) - The figure shows the stepwise formation of an electrochemical cell.    Specimen (13)    Unshaped brass shim (14)    Kapton polyimide films (15)    Brass jacket (16)