Positive electrode active material including lithium-containing complex phosphate elliptical particles, power storage device, electronic device, and method for manufacturing: positive electrode active material

An active material comprising:

• a secondary particle comprising a first primary particle, a second primary particle and a third primary particle,
• wherein each of the first primary particle, the second primary particle and the third primary particle comprises a lithium-containing complex phosphate,
• wherein each of the first primary particle, the second primary particle and the third primary particle comprises a major diameter in a major axis and a minor diameter in a minor axis when observed with a microscope,
• wherein the major diameter of the first primary particle is 2.2 to 5.0 times larger than the minor diameter of the first primary particle, and the minor diameter of the first primary particle is more than or equal to 33 nm and less than or equal to 125 nm,
• wherein the major diameter of the second primary particle is 2.2 to 5.0 times larger than the minor diameter of the second primary particle, and the minor diameter of the second primary particle is more than or equal to 33 nm and less than or equal to 125 nm,
• wherein the major diameter of the third primary particle is 2.2 to 5.0 times larger than the minor diameter of the third primary particle, and the minor diameter of the third primary particle is more than or equal to 33 nm and less than or equal to 125 nm,
• wherein the second primary particle is in contact with the first primary particle and the third primary particle, and
• wherein the major axes of the first primary particle, the second primary particle and the third primary particle make angles more than or equal to 0° and less than or equal to 10°.