NOVELTY - High-manganese polycrystal positive material (I) comprises: at least two crystal lattice structures of lithium manganese oxide, lithium cobalt nickel manganese oxide compound, lithium nickel cobalt oxide compound, lithium cobalt oxide, lithium nickel manganese oxides and lithium nickel oxide; and the crystalline phases are in the mixed and symbiotic state, where the weight of manganese is greater than or equal to 40% and the grain diameter is 7-20 microns.    USE - The high-manganese polycrystal positive material is useful in a power lithium ion cell applied to the bicycle, electric automobile and industrial energy-storing systems, as wind power, nuclear power, solar energy and power grid peak load regulation.    ADVANTAGE - The high-manganese polycrystal positive material: exhibits specific energy of 155 Wh/Kg and above, recycle capacity of 500 times of 1C charging/discharging at 55 degrees C not less than 80%, recycle service life not less than 1000 times at 25 degrees C, capacity greater than 80%; and good performance; and improves the energy density and high-temperature recycle performance of the cell.    DETAILED DESCRIPTION - High-manganese polycrystal positive material (I) of formula (LiwMnx(CoNi)yOz) comprises: at least two crystal lattice structures of lithium manganese oxide, lithium cobalt nickel manganese oxide compound of formula (LiCon(NiMn)1-n), lithium nickel cobalt oxide compound of formula (LiNi(0.8)Co(0.2)O2, lithium cobalt oxide, lithium nickel manganese oxides of formula (LiNinMn1-nO2) and (LiMn2nNi2(1-n)O4) and lithium nickel oxide; and the crystalline phases are in the mixed and symbiotic state, where the weight of manganese is greater than or equal to 40% and the grain diameter is 7-20 microns.    Either x = 0.4-2;    y = 0.1-0.6; or    x+y = less than 2;    z = greater than or equal to 2;    w = greater than or equal to 1; and    n = less than 1.    INDEPENDENT CLAIMS are also included for:    (1) preparing (I) comprising precursor preparation; single crystal sintering; and polycrystal synthesis. The step of the precursor preparation comprises dispersing lithium carbonate, lithium acetate or lithium hydroxide with lithium content of 0.3-1.2 mol into the polyvinylidene aqueous colloid (200-300 ml) at the rotating speed of 10-60 rpm for 50-120 minutes to prepare the colloidal body and adding the cobalt, nickel, manganese compound into the colloidal body based on the manganese and nickel and cobalt ratio of 0.4-2.0: 0.01-0.6 at 50-60 rpm for 2-30 minutes to obtain the crystal phase precursor of cobalt, nickel and manganese. The step of single crystal sintering comprises sintering the crystal phase precursor at 750-1000 degrees C for 4-15 hours, cooling it and crushing it so that the grain diameter (D50) is 7-20 microns, to obtain lithium manganese oxide, lithium cobalt nickel manganese oxide compound, lithium nickel cobalt oxide compound, lithium cobalt oxide, lithium nickel manganese oxides or lithium nickel oxide. The step of polycrystal synthesis comprises mixing at least two single crystal compounds based on the proportion that the manganese content is 60-90% of the mol percentage content of cobalt, nickel and manganese at the rotating speed of 100-150 rpm for 5-20 minutes to obtain the mixture, dissolving the soluble salt compound of aluminum, silicon, titanium, iron, zirconium, magnesium and/or chromium of 0.01-0.1 mol into 30-60% ethanol aqueous solution (100-300 ml), adding the mixture and mixing them at the rotating speed of 60-100 rpm for 30-60 minutes and drying it at 100-200 degrees C for 2-10 hours, and heating it at 50-100 degrees C per hour to 300-850 degrees C and activating it for 2-10 hours to finish the crystal phases mixture or symbiosis; and    (2) a power lithium ion cell having an positive collector coated with an positive active substance, where the positive active substance is (I), the crystal lattice is doped with aluminum, silicon, titanium, iron, zirconium, magnesium and chromium, the doping quantity is 0.01-0.1 mol/mol of (I), the weight of manganese is greater than or equal to 40% of the weight of (I), the content of manganese is 60-90% of the total mol quantity of cobalt, nickel and manganese, the grain diameter is 7-20 microns; the XRD of the high-manganese polycrystal positive material displays the crystal lattice structure and crystalline phases are in the mixed and symbiotic state.