NOVELTY - A positive active composition comprises a substituted lithium nickel-manganese oxide having spherical morphology.    USE - For rechargeable batteries for products e.g. electric vehicles, hybrid electric vehicles, portable electronics and a variety of other products.    ADVANTAGE - The inventive composition is less expensive and thermally safer than existing cathode materials e.g. lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2). It also exhibits improved calendar/cycle life when compared to existing cathode materials.    DETAILED DESCRIPTION - A positive active composition comprises a substituted lithium nickel-manganese oxide having spherical morphology. The substituted lithium nickel-manganese oxide has the formula:    Li1+xNialphaCobetaMngammaM'deltaOyFz    M' = Mg, Zn, Al, Ga, B, Zr, or Ti    x = 0-0.333    alpha = 0-1    beta = 0-1    gamma = 0-2    delta = 0-0.2    y = 2-4    z = 0-0.5    INDEPENDENT CLAIMS are also included for:    (1) a mixed nickel-cobalt-manganese carbonate comprising (NiaCobMnc)CO3 having a spherical morphology;    (2) a positive electrode material, having the positive active composition, a conducting agent and a binder;    (3) a non-aqueous lithium cell, having the positive electrode material, a negative electrode and a non-aqueous electrolyte;    (4) a method of preparing the mixed nickel-cobalt-manganese carbonate comprising dissolving in distilled water 0.01-2M of a metal solution comprising a nickel (Ni) compound from Ni-acetate, Ni-nitrate and/or Ni-sulfate, a cobalt (Co) compound from Co-acetate, Co-nitrate and/or Co-sulfate, and a manganese (Mn) compound from Mn-acetate, Mn-nitrate and/or Mn-sulfate, adding the metal solution to an aqueous solution of 0.1-5M of a carbonate from ammonium hydrogen carbonate and/or sodium carbonate and aging the precipitates in the solution at a temperature increased from 20-65 degrees C, where the solution is reacted at each temperature for 1-24 hours; and    (5) a method of preparing the positive active composition, comprising mixing amounts of lithium hydroxide (or lithium carbonate or lithium nitrate), the nickel-cobalt-manganese carbonate as above, 1,M'-hydroxide (or M'-carbonate or M'-oxide) and lithium fluoride (LiF, or ammonium fluoride (NH4F)) for 12-24 hours to form a mixed powder, calcinating the mixed powder at 450-700 degrees C for 12-30 hours either in air or in oxygen atmospheres and calcinating the mixed powder at 700 to 1000 degrees C for 10-24 hours either in air or in oxygen atmospheres.    a, b, c = 0-1    M' = as defined above