LITHIUM-ION SECONDARY BATTERY POSITIVE ELECTRODE MATERIAL AND METHOD FOR MANUFACTURING SAME, LITHIUM-ION SECONDARY BATTERY POSITIVE ELECTRODE, AND LITHIUM-ION SECONDARY BATTERY

Provided is a positive electrode material for a lithium ion secondary battery, including aggregated particles including aggregated multiple primary particles of a positive electrode active substance containing lithium iron phosphate coated with a carbonaceous film, the positive electrode active substance having a prescribed composition containing lithium iron phosphate, the positive electrode material having a change rate of a lattice area of a b-c axis plane before charging and after full charging (((lattice area before charging-lattice area after full charging)/lattice area before charging)×100) of 1.10% or more and 1.33% or less. The positive electrode material has excellent cycle characteristics and high input and output characteristics in using as a positive electrode of a lithium ion secondary battery.