TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Disclosed): Lithium manganese(IV) nickel(III) oxide is prepared by mixing metallic compound raw material and molten salt raw material to produce raw material mixture, preparing metal salt-containing aqueous solution, making aqueous solution alkaline, depositing metal hydroxide precipitate, filtering and washing metal hydroxide precipitate with water to produce metal hydroxide precursor, preparing metal oxide precursor and mixing with raw material mixture, heating, producing molten salt, precipitating black product, mixing molten salt and black product, forming black suspension, filtering black suspension, washing filter cake with acetone, vacuum drying, producing black solid, pulverizing black solid, and obtaining black powder. SPECIFIC COMPOUNDS - 3 Compounds (1) are disclosed, e.g. Li(Li0.25Mn0.5Ni0.125Co0.125)O2, Li(Li0.2Mn0.54Ni0.13Co0.13)O2, and Li(Li0.2Mn0.4Ni0.4)O2.    EXAMPLE - A nickel manganese cobalt (NiMnCo) oxide (0.02 mol) was mixed with lithium hydroxide monohydrate (LiOH.H2O) (8.4 g), and raw material mixture was prepared. Manganese nitrate hexahydrate (Mn(NO3)2.6H2O) (192.3 g), cobalt nitrate hexahydrate (Co(NO3)2.6H2O) (46.6 g), and nickel nitrate (Ni(NO3 )2.6H2O) (46.5 g) were dissolved in distilled water (500 ml), and metal salt-containing aqueous solution was produced. Metal salt-containing aqueous solution was stirred in ice bath, lithium hydroxide monohydrate (LiOH.H2O) (50 g) in distilled water (300 ml) was dripped for 2 hours, aqueous solution was made alkaline, and metal hydroxide precipitate was deposited. Metal hydroxide precipitate was filtered, and metal hydroxide precursor of Mn:Co:Ni=0.67:0.16:0.16 was obtained by washing with distilled water. Metal oxide (NiMnCo oxide) precursor was prepared, raw material mixture was placed in crucible, crucible was moved to 700 degrees C electric furnace and heated for 2 hours, molten salt was prepared, and black product was precipitated. Molten salt was cooled, solidified, and mixed with black product which was immersed in ion-exchange water, mixture was stirred, and black suspension was produced. Black suspension was filtered, filter cake was washed with acetone, vacuum drying was performed, and black solid was produced and pulverized. Black powder was dissolved in concentrated hydrochloric acid and subjected to inductively coupled plasma analysis. Black powder was verified to be Li(Li0.25Mn0.5Ni0.125Co0.125)O2.