POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM SECONDARY BATTERIES AND MANUFACTURING METHOD THEREOF, AND LITHIUM SECONDARY BATTERY ARRANGED BY USE OF SUCH POSITIVE ELECTRODE ACTIVE MATERIAL

PROBLEM TO BE SOLVED: To provide a lithium secondary battery having both of a high level of safety and a high capacity and superior in cycle life by use of a fine and high-performance positive electrode active material for lithium secondary batteries which can offer a high capacity, and to provide a precursor used to obtain the positive electrode active material for lithium secondary batteries and a manufacturing method thereof, and a manufacturing method thereof suitable for industrial production.SOLUTION: A positive electrode active material for lithium secondary batteries comprises a metal lithium silicate salt expressed by the general formula, LiMSiO(1.90≤x≤2.15; 0.90≤y≤1.10; and M is at least one element selected from Mn, Fe, Ni and Co). The positive electrode active material includes: metal lithium silicate salt particles consisting of primary particles and secondary particles composed of agglomerations of the primary particles. The primary particles have diameters of 10-300 nm according to measurement by SEM observation. The positive electrode active material has a specific surface area of 25-35 m/g, and a carbon content of 3-7 mass%. Contact faces through which the metal lithium silicate salt particles contact an electrolyte are at least partially covered with a carbonaceous material having conductivity.