Power storage device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorTakahiro KAWAKAMI
Life of this patent
Estimating the term…
Abstract
A power storage device including 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 therebetween is provided. The positive electrode active material includes a first region which includes a compound containing lithium and one or more of manganese, cobalt, and nickel; and a second region which covers the first region and includes a compound containing lithium and iron. Since a superficial portion of the positive electrode active material includes the second region containing iron, an energy barrier when lithium is inserted into and extracted from the surface of the positive electrode active material can be decreased.
Claims23
A power storage device comprising:
- a positive electrode comprising:
- a positive electrode current collector;
- and
- a positive electrode active material over the positive electrode current collector;
- and
- a negative electrode facing the positive electrode with an electrolyte interposed therebetween,
- wherein the positive electrode active material comprises:
- a first portion;
- and
- a second portion which covers at least part of the first portion,
- wherein the first portion has higher iron concentration than the second portion.
A power storage device comprising:
- a positive electrode comprising:
- a positive electrode current collector;
- and
- a positive electrode active material over the positive electrode current collector;
- and
- a negative electrode facing the positive electrode with an electrolyte interposed therebetween,
- wherein the positive electrode active material comprises:
- a first region which includes a compound containing lithium and one or more of manganese, cobalt, and nickel;
- and
- a second region which covers the first region and includes a compound containing lithium and iron.
A power storage device comprising:
- a positive electrode comprising:
- a positive electrode current collector;
- and
- a positive electrode active material over the positive electrode current collector;
- and
- a negative electrode facing the positive electrode with an electrolyte interposed therebetween,
- wherein the positive electrode active material is in particle form,
- wherein the positive electrode active material includes a compound containing lithium, iron, and one or more of manganese, cobalt, and nickel,
- wherein the positive electrode active material comprises a region including a surface of the positive electrode active material, and
- wherein iron concentration of the region monotonically increases from a center of the positive electrode active material to the surface of the positive electrode active material.
A power storage device comprising:
- a positive electrode comprising:
- a positive electrode current collector;
- and
- a positive electrode active material over the positive electrode current collector;
- and
- a negative electrode facing the positive electrode with an electrolyte interposed therebetween,
- wherein the positive electrode active material is in film form,
- wherein the positive electrode active material includes a compound containing lithium, iron, and one or more of manganese, cobalt, and nickel,
- wherein the positive electrode active material comprises a region including a top surface of the positive electrode active material, and
- wherein iron concentration of the region monotonically increase from the positive electrode current collector to the top surface of the positive electrode active material.
Dependencies are inferred from the claim text.