Negative electrode, method for producing the same, and battery
A method for producing a negative electrode, including a step of subjecting a copper foil to a plasma treatment, a step of coating the copper foil subjected to the plasma treatment, with a slurry including an active material containing a silicon atom, and a step of subjecting the copper foil coated with the slurry to a heat treatment to form an intermetallic compound of copper and silicon at an interface between the copper foil and the active material. A negative electrode including a copper foil, an active material layer including an active material containing a silicon atom on the copper foil, and copper silicide at an interface between the copper foil and the active material.
1. A method for producing a negative electrode, comprising:
subjecting a copper foil to a plasma treatment,
coating the copper foil subjected to the plasma treatment, with a slurry comprising an active material containing a silicon atom, and
subjecting the copper foil coated with the slurry to a heat treatment to form an intermetallic compound of copper and silicon at an interface between the copper foil and the active material.
2. The method for producing a negative electrode according to claim 1 , wherein
the active material comprises at least one material selected from the group consisting of silicon and silicon oxide, and
the intermetallic compound is copper silicide.
3. The method for producing a negative electrode according to claim 1 , wherein
the plasma treatment is performed using a mixed gas containing argon and ammonia, and
a flow rate ratio of argon and ammonia in the mixed gas, argon/ammonia, is 2 to 5.
4. The method for producing a negative electrode according to claim 3 , wherein the plasma treatment is performed under a condition where a flow rate of the mixed gas is 200 to 300 sccm, a plasma output voltage is 1 to 5 kW, and a distance between a plasma source and the copper foil is 10 to 30 mm.
5. The method for producing a negative electrode according to claim 1 , wherein the heat treatment is performed under a condition where a temperature is 250 to 330° C. and a heating time is 30 minutes to 2 hours.
6. A negative electrode comprising:
a copper foil,
an active material layer comprising an active material containing a silicon atom and a binder on the copper foil, and
copper silicide at an interface between the copper foil and the active material.
7. The negative electrode according to claim 6 , wherein the active material comprises at least one material selected from the group consisting of silicon and silicon oxide.
8. The negative electrode according to claim 6 , further comprising a conductivity imparting material.
9. A battery comprising the negative electrode according to claim 6 .
10. The battery according to claim 9 , wherein the battery is a lithium ion secondary battery.
11. A battery comprising the negative electrode according to claim 7 .
12. The battery according to claim 11 , wherein the battery is a lithium ion secondary battery.
13. A battery comprising the negative electrode according to claim 8 .
14. The battery according to claim 13 , wherein the battery is a lithium ion secondary battery.
15. The negative electrode according to claim 6 , wherein the binder is polyimide.
16. The negative electrode according to claim 8 , wherein the conductivity imparting material is carbon.
17. A battery comprising the negative electrode according to claim 15 .
18. The battery according to claim 17 , wherein the battery is a lithium ion secondary battery.
19. A battery comprising the negative electrode according to claim 16 .
20. The battery according to claim 19 , wherein the battery is a lithium ion secondary battery.