TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: In the method (M1), the first crystalline substance and the second crystalline substance as a molar ratio of 1 to 0.01-0.05; and the amount of Fe used is 90-100 mol.%. The method (M1) further involves sintering a carbon additive with the two crystalline substances to provide the mixed crystal with 1-5 wt.% carbon. In the method (M1) and (M2), the second crystalline substance is prepared by heating the oxide compounds of A', B' and N' at a molar ratio of a:b:c at 400-1000 degrees C for 8-15 hours; the sintering step has a heating rate of 5-20 degrees C/minute with a sintering temperature of 500-800 degrees C and a sintering time of 5-32 hours. In the method (M2), the lithium, iron and phosphorus (Li:Fe:P) sources have a molar ratio of 0.95-1.1:1:0.95-1.1, where the first material and the second material has a molar ratio of 1 to 0.01-0.05; and the carbon source provides the mixed crystal with 1-5 wt.% carbon, where the carbon source includes carbon black, acetylene black, graphite, glucose, sucrose, citric acid, starch, dextrin or polyethylene glycol. Preferred Components: The first crystalline substance includes at least one member selected from LiFePO4, LiMnPO4, LiCoPO4, Li3Fe2(PO4)3, LiTi2(PO4), Li3V2(PO4), Li2NaV2(PO4), Li0.99Y0.01FePO4, Li(R)i(Fe)1-iPO4, LiTiPO5, LiVMoO6, LiVWO6, LiVP2O7 and LiFeAs2O7; or LiFePO4, Li0.99Y0.01FePO4 and LiRiFe0-iPO4. The second crystalline substance includes at least one member selected from Bi4Ti3O12, CuNb2O6, MnTaO4, FeWO4, ZnZrNb2O8, NiNb2O6, NiZrNb2O8, FeTiNb2O8, MnTiNb2O8, MgSnNb2O8, ZnTa2O6, Cu0.85Zn0.15Nb2O6, YBa3Ti2O8.5, Zr0.75Ti0.75Sn0.5O4, HfTiO4 and MgNb2O6. The lithium source includes lithium carbonate, lithium hydroxide, lithium oxalate or lithium acetate; the iron source includes ferrous oxalate, ferrous carbonate, iron acetate, iron oxide, iron phosphate, iron pyrophosphate or iron nitrate; and the phosphate source includes ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, iron phosphate, phosphoric acid or lithium dihydrogen phosphate. The first material further includes a carbon source.i=0-0.1;R=members selected from elements Mn, Co, Ni, Ti, Mg, Ca and Zn.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The carbon additive includes at least one member selected from carbon black, acetylene black, graphite, glucose, sucrose, citric acid, starch, dextrin and polyethylene glycol. EXAMPLE - A Y2O3, BaCO3 and TiO2 were mixed in a molar ratio of 0.5:3:2, grind the mixture in a ball mill for 5 hours, heat it in a nitrogen atmosphere at a heating rate of 7 degrees C per minute to 1000 degrees C and continue sintering the product for 15 hours, to give YBa3Ti2O8 S by comparing it with a standard XRD pattern Of YBa3Ti2O8.5. The YBa3Ti2O8.5 was mixed with LiFePO4 in a molar ratio of 1:0.02 with carbon black as a source of carbon (amount of carbon capable of providing 2 wt.% of carbon content in the final product). The LiFePO4 can be prepared by mixing lithium hydroxide, ferrous carbonate and phosphoric acid in a Li:Fe:P molar ratio of 1.05:1:1.05, which can be added to the YBa3Ti2O8.5 at a phosphoric acid to YBa3Ti2O8.5 molar ratio of 1:0.02 (taking into account the phosphorus components in the mixture). The mixture was grind in a ball mill for 10 hours, remove and dry at 80 degrees C. Heat the resulting powder in a nitrogen or argon atmosphere at a heating rate of 20-800 degrees C per minute, continue sintering the product for 8 hours to give cathode active material having LiFePO4/YBa3Ti2O8.5/C in a mixed crystal form.