NOVELTY - A positive-electrode active material comprises particles of metallic lithium silicate. The particles consist of secondary particles formed by aggregating primary particles. The primary particle diameter is 10-300 nm and the secondary particle diameter is 0.5-10 mu m. The active material has a specific surface area of 25-35 m2/g and a carbon content of 3-7 %mass.    USE - Positive-electrode active material is used for lithium secondary batteries (claimed). Uses include but are not limited to mobile telephones, notebook computers, information technology apparatus, hybrid vehicles, plug-in hybrid vehicles, electric vehicles, components used for electric power leveling, and components used for electric power storage.    ADVANTAGE - The positive-electrode active material provides lithium secondary batteries having excellent safety, capacity, and cycle life.    DETAILED DESCRIPTION - A positive-electrode active material comprises particles of metallic lithium silicate of formula: LixMySiO4. The particles consist of secondary particles formed by aggregating primary particles. The primary particle diameter is 10-300 nm and the secondary particle diameter is 0.5-10 mu m. The active material has a specific surface area of 25-35 m2/g and a carbon content of 3-7 %mass.    x=1.9-2.15;    y=0.9-1.1;and    M=manganese, iron, nickel or cobalt.    INDEPENDENT CLAIMS are included for the following:    (1) precursor, which is an amorphous coprecipitate of element (M) obtained by mixing a solution containing bivalent ion of element (M) of metal silicate of formula: MySiO3, and a solution containing silicate ion and silicic acid;    (2) manufacture of precursor, which involves mixing solution containing bivalent ion of element (M) and solution containing silicate ion, controlling pH, maintaining pH to 8-11, crystallizing coprecipitate, washing with water, and drying after solid-liquid separation; and    (3) manufacture of positive-electrode active material, which involves mixing the precursor with a lithium compound and a carbon source, and baking at 450-750 degrees C in a non-oxidizing atmosphere.