Power storage device and method for manufacturing the same
View Patent ↗To provide a power storage device with improved cycle characteristics and a method for manufacturing the power storage device, a power storage device is provided with a conductive layer in contact with a surface of an active material layer including a silicon layer after an oxide film, such as a natural oxide film, which is formed on the surface of the active material layer is removed. The conductive layer is thus provided in contact with the surface of the active material layer including a silicon layer, whereby the conductivity of the electrode surface of the power storage device is improved; therefore, cycle characteristics of the power storage device can be improved.
1. A power storage device comprising:
a current collector;
an active material layer over the current collector, the active material layer having:
a first region comprising crystalline silicon; and
a second region comprising crystalline silicon protrusions on the first region, wherein the crystalline silicon protrusions continuously extend from the first region; and
a conductive layer which is on and in contact with a surface of the second region of the active material layer.
2. The power storage device according to claim 1 , wherein the conductive layer comprises one or more of copper, nickel, titanium, manganese, cobalt, and iron.
3. The power storage device according to claim 1 , further comprising silicide of the conductive layer in the conductive layer or between the conductive layer and the active material layer.
4. The power storage device according to claim 1 , wherein the conductive layer comprises a second silicon layer containing phosphorus or boron.
5. The power storage device according to claim 1 , wherein a longest length of the crystalline silicon protrusions is 15 μm to 20 μm.
6. A power storage device comprising:
a current collector comprising a metal element;
a mixed layer comprising the metal element and silicon on the current collector;
an active material layer over the mixed layer, the active material layer having:
a first region comprising crystalline silicon; and
a second region comprising crystalline silicon protrusions on the first region, wherein the crystalline silicon protrusions continuously extend from the first region; and
a conductive layer which is on and in contact with a surface of the second region of the active material layer.
7. The power storage device according to claim 6 , wherein a thickness of the conductive layer is greater than or equal to 0.1 nm and less than or equal to 10 nm.
8. The power storage device according to claim 6 , wherein the conductive layer comprises one or more of copper, nickel, titanium, manganese, cobalt, and iron.
9. The power storage device according to claim 6 , further comprising silicide of the conductive layer in the conductive layer or between the conductive layer and the active material layer.
10. The power storage device according to claim 6 , wherein the conductive layer comprises a second silicon layer containing phosphorus or boron.
11. The power storage device according to claim 6 , wherein a diameter of one of the crystalline silicon protrusions near its root in the second region is 1 μm to 2 μm.
12. The power storage device according to claim 6 , wherein a longest length of the crystalline silicon protrusions is 15 μm to 20 μm.
13. A power storage device comprising:
a current collector comprising a metal element;
a mixed layer comprising the metal element and silicon on the current collector;
a metal oxide layer comprising the metal element on the mixed layer;
an active material layer on the metal oxide layer, the active material layer having:
a first region comprising crystalline silicon; and
a second region comprising crystalline silicon protrusions on the first region, wherein the crystalline silicon protrusions continuously extend from the first region; and
a conductive layer which is on and in contact with a surface of the second region of the active material layer.
14. The power storage device according to claim 13 , wherein the metal element is selected form the group consisting of platinum, aluminum, copper, titanium, zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, and nickel.
15. The power storage device according to claim 13 , wherein a thickness of the conductive layer is greater than or equal to 0.1 nm and less than or equal to 10 nm.
16. The power storage device according to claim 13 , wherein the conductive layer comprises one or more of copper, nickel, titanium, manganese, cobalt, and iron.
17. The power storage device according to claim 13 , wherein the conductive layer comprises a second silicon layer containing phosphorus or boron.
18. The power storage device according to claim 13 , wherein a diameter of one of the crystalline silicon protrusions near its root in the second region is 1 μm to 2 μm.
19. The power storage device according to claim 13 , wherein a longest length of the crystalline silicon protrusions is 15 μm to 20 μm.
20. The power storage device according to claim 1 , wherein a thickness of the conductive layer is greater than or equal to 0.1 nm and less than or equal to 10 nm.
21. The power storage device according to claim 1 , wherein the current collector comprises at least one metal element selected form the group consisting of platinum, aluminum, copper, titanium, zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, and nickel.
22. The power storage device according to claim 6 , wherein the metal element is selected form the group consisting of platinum, aluminum, copper, titanium, zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, and nickel.