Electrode for energy storage device and method for manufacturing the same
An electrode for an energy storage device with less deterioration due to charge and discharge, and a method for manufacturing thereof are provided. Further, an energy storage device having large capacity and high endurance can be provided. In an electrode of an energy storage device in which an active material is formed over a current collector, the surface of the active material is formed of a crystalline semiconductor film having a {110} crystal plane. The crystalline semiconductor film having a {110} crystal plane may be a crystalline silicon film containing a metal element which reacts with silicon to form a silicide. Alternatively, the crystalline semiconductor film having a {110} crystal plane may be a crystalline semiconductor film containing silicon as its main component and also containing germanium and a metal element which reacts with silicon to form a silicide.
1. An electrode for an energy storage device comprising:
a current collector; and
an active material formed over the current collector,
wherein a surface of the active material is formed of a crystalline semiconductor film having a {110} crystal plane, and
wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%.
2. The electrode for an energy storage device according to claim 1 , wherein the crystalline semiconductor film having a {110} crystal plane is a crystalline silicon film containing a metal element.
3. The electrode for an energy storage device according to claim 1 , wherein the crystalline semiconductor film having a {110} crystal plane contains silicon as its main component and also contains germanium and a metal element.
4. The electrode for an energy storage device according to claim 2 , wherein the metal element is a metal element which reacts with silicon to form a silicide.
5. The electrode for an energy storage device according to claim 2 , wherein the metal element is selected from the group consisting of zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, and platinum.
6. The electrode for an energy storage device according to claim 1 , wherein the current collector is stainless steel, copper, or nickel.
7. An electrode for an energy storage device comprising:
a current collector; and
an active material formed over the current collector, the active material including a stack of:
a crystalline semiconductor film being in contact with the current collector and containing silicon as its main component and also containing germanium; and
a crystalline silicon film being in contact with the crystalline semiconductor film, and having a {110} crystal plane,
wherein an orientation ratio of the crystalline silicon film on {110} plane is greater than or equal to 20%.
8. The electrode for an energy storage device according to claim 7 , wherein the metal element is a metal element which reacts with silicon to form a silicide.
9. The electrode for an energy storage device according to claim 7 , wherein the metal element is selected from the group consisting of zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, and platinum.
10. The electrode for an energy storage device according to claim 7 , wherein the current collector is stainless steel, copper, or nickel.
11. An electrode for an energy storage device comprising:
a current collector; and
an active material formed over the current collector, the active material including a stack of:
a crystalline semiconductor film in contact with the current collector, the crystalline semiconductor film including silicon as its main component and a metal element and germanium; and
a crystalline silicon film in contact with the crystalline semiconductor film, the crystalline silicon film including the metal element,
wherein each of the crystalline semiconductor film and the crystalline semiconductor film has a {110} crystal plane,
wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%, and
wherein an orientation ratio of the crystalline silicon film on {110} plane is greater than or equal to 20%.
12. The electrode for an energy storage device according to claim 11 , wherein the metal element is a metal element which reacts with silicon to form a silicide.
13. The electrode for an energy storage device according to claim 11 , wherein the metal element is selected from the group consisting of zirconium, titanium, hathium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, and platinum.
14. The electrode for an energy storage device according to claim 11 , wherein the current collector is stainless steel, copper, or nickel.
15. A method for manufacturing an electrode for an energy storage device comprising the steps of:
forming an amorphous semiconductor film containing silicon as its main component and also containing germanium over a current collector;
adding a metal element to the amorphous semiconductor film; and
performing heat treatment on the amorphous semiconductor film after adding the metal element, whereby forming a crystalline semiconductor film;
wherein the crystalline semiconductor film has a {110} crystal plane, and
wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%.
16. The method for manufacturing an electrode for an energy storage device according to claim 15 , wherein the metal element is a metal element which reacts with silicon to form a silicide.
17. The method for manufacturing an electrode for an energy storage device according to claim 15 , wherein the metal element is selected form the group consisting of zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, and platinum.
18. The method for manufacturing an electrode for an energy storage device according to claim 15 , wherein the current collector is stainless steel, copper, nickel, tungsten, or molybdenum.
19. A method for manufacturing an electrode for an energy storage device comprising the steps of:
forming an amorphous semiconductor film containing silicon as its main component and germanium over a current collector;
forming an amorphous silicon film over the amorphous semiconductor film;
adding a metal element to the amorphous semiconductor film and the amorphous silicon film;
performing heat treatment on the amorphous semiconductor film and the amorphous silicon film after adding the metal element to crystallize the amorphous semiconductor film and the amorphous silicon film, whereby forming a crystalline semiconductor film and forming a crystalline silicon film over the crystalline semiconductor film;
wherein each of the crystalline semiconductor film and the crystalline silicon film has a {110} crystal plane,
wherein an orientation ratio of the crystalline semiconductor film on {110} plane is greater than or equal to 20%, and
wherein an orientation ratio of the crystalline silicon film on {110} plane is greater than or equal to 20%.
20. The method for manufacturing an electrode for an energy storage device according to claim 19 , wherein the metal element is a metal element which reacts with silicon to form a silicide.
21. The method for manufacturing an electrode for an energy storage device according to claim 19 , wherein the metal element is selected form the group consisting of zirconium, titanium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, nickel, and platinum.
22. The method for manufacturing an electrode for an energy storage device according to claim 19 , wherein the current collector is stainless steel, copper, nickel, tungsten, or molybdenum.