Power storage device

A power storage device comprising:

• a positive electrode in which a positive electrode active material is formed over a positive electrode current collector;
• and
• a negative electrode which faces the positive electrode with an electrolyte interposed between the negative electrode and the positive electrode,
• wherein the positive electrode active material comprises:
• a first region comprising a phosphate compound containing lithium and nickel;
• and
• a second region comprising a phosphate compound containing lithium and one or more of iron, manganese, and cobalt, but not containing nickel,
• wherein the first region is covered with the second region,
• wherein the first region is in direct contact with a surface of the positive electrode current collector, and
• wherein the second region is in direct contact with the surface of the positive electrode current collector.

A power storage device comprising:

• a positive electrode in which a positive electrode active material is formed over a positive electrode current collector;
• and
• a negative electrode which faces the positive electrode with an electrolyte interposed between the negative electrode and the positive electrode,
• wherein the positive electrode active material comprises:
• a plurality of first regions comprising a phosphate compound containing lithium and nickel;
• and
• a second region comprising a phosphate compound containing lithium and one or more of iron, manganese, and cobalt, but not containing nickel,
• wherein the plurality of first regions are covered with the second region,
• wherein the plurality of first regions are in direct contact with a surface of the positive electrode current collector, and
• wherein the second region is in direct contact with the surface of the positive electrode current collector.