| abstract |
PROBLEM TO BE SOLVED: To provide a positive electrode active material having olivine type lithium iron phosphate fine particles and capable of constituting a lithium ion secondary battery with good characteristics, and a method for producing the positive electrode active material. A positive electrode active material for a lithium ion secondary battery having at least olivine-type lithium iron phosphate fine particles, which is present as a single particle without forming a secondary aggregate. The iron lithium fine particles are a positive electrode active material for a lithium ion secondary battery having an average particle size of 5 to 50 nm and a particle size of 90% or more of all particles in the range of 3 to 70 nm. The positive electrode active material for a lithium ion secondary battery uses iron oxide fine particles having an average particle size of 50 nm or less as a growth nucleus, and the iron oxide fine particles are mixed with a solution containing a lithium source and a phosphate source, Produced by heating the resulting mixture. [Selection] Figure 2 |