POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, ITS MANUFACTURE, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY USING POSITIVE ELECTRODE ACTIVE MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a positive electrode active material for a nonaqueous electrolyte secondary battery, whereby the discharge capacity of the battery, its high-efficiency discharge capacity and the rate of retention of the discharge capacity are enhanced. SOLUTION: A positive electrode active material for a nonaqueous electrolyte secondary battery uses a lithium cobalt oxide represented by the formula LiCoO2 , and the lithium cobalt oxide is made of a mixture of primary particles of small crystals whose projected diagrams as observed with a SEM(scanning electron microscope) have Feret's diameters in the range of 0.4 to 10 μm and whose average particle diameters are 5 μm or less and secondary particles comprising a number of collected small crystals in the range from 4 to 30 μm. The mole ratio of Co to Li is from 0.97 to 1.03 inclusive.