Anode layer, lithium secondary battery including anode layer, and method of manufacturing anode layer
Example embodiments relate to an anode layer of a lithium secondary battery. The anode layer includes a three-dimensional carbon structure and a plurality of silicon particles. The three-dimensional carbon structure includes a plurality of cavities without a binder, and the plurality of silicon particles are disposed in the plurality of cavities.
1. An anode layer of a lithium secondary battery, the anode layer comprising:
a three-dimensional carbon structure including a plurality of cavities without a binder; and
at least one silicon particle in at least one of the plurality of cavities;
wherein at least one of the plurality of cavities includes an empty space; and
a volume of the at least one of the plurality of cavities is larger than a volume of the at least one silicon particle so that a change in the volume of the at least one silicon particle does not cause a change in volume of the anode layer.
2. The anode layer of claim 1 , wherein the carbon structure comprises at least one of graphene, a reduced graphene oxide, and graphite.
3. The anode layer of claim 1 , wherein a volume of the at least one silicon particle in the at least one of the plurality of cavities is about 30% to about 70% of a total volume of the at least one of the plurality of cavities.
4. The anode layer of claim 1 , wherein the at least one silicon particle has a size of about 5 nm to about 30 μm.
5. The anode layer of claim 1 , wherein the anode layer has a planar size of about 1 mm to about 1 m.
6. A lithium secondary battery comprising an anode layer including:
a three-dimensional carbon structure including a plurality of cavities without a binder; and
at least one silicon particle in at least one of the plurality of cavities;
wherein at least one of the plurality of cavities includes an empty space; and
a volume of the at least one of the plurality of cavities is larger than a volume of the at least one silicon particle so that a change in the volume of the at least one silicon particle does not cause a change in volume of the anode layer.
7. The lithium secondary battery of claim 6 , wherein the three-dimensional carbon structure comprises at least one of graphene, a reduced graphene oxide, and graphite.
8. The lithium secondary battery of claim 6 , wherein a volume of the at least one silicon particle in the at least one of the plurality of cavities is about 30% to about 70% of a total volume of the at least one of the plurality of cavities.
9. The lithium secondary battery of claim 6 , wherein the at least one silicon particle has a size of about 5 nm to about 30 μm.
10. The lithium secondary battery of claim 6 , wherein the anode layer has a planar size of about 1 mm to about 1 m.
11. A method of manufacturing an anode layer of a lithium secondary battery, the method comprising:
forming a pre-carbon structure including a plurality of first cavities without a binder, each of the plurality of first cavities having a first opening for exposing a corresponding one of the plurality of first cavities to an outside thereof;
disposing at least one silicon particle in at least one of the plurality of first cavities through the first opening; and
joining a carbon sheet to the pre-carbon structure to close the first opening of the at least one of the plurality of first cavities;
wherein the at least one of the plurality of first cavities includes an empty space; and
a volume of the at least one of the plurality of first cavities is larger than a volume of the at least one silicon particle so that a change in the volume of the at least one silicon particle does not cause a change in volume of the anode layer.
12. The method of claim 11 , wherein the forming of the pre-carbon structure comprises:
forming a polyimide structure having a plurality of second cavities, each of the plurality of second cavities having a second opening at one side thereof;
inserting a first heat-resistant member into the plurality of second cavities and disposing a second heat-resistant member to surround the polyimide structure;
heating the polyimide structure with the first and second heat-resistant members disposed thereat; and
removing the first and second heat-resistant members.
13. The method of claim 12 , wherein the first and second heat-resistant members comprise a silicon carbide.
14. The method of claim 12 , wherein the heating of the polyimide structure comprises heating the polyimide structure from about 2800° C. to about 3200° C.
15. The method of claim 11 , wherein the forming of the pre-carbon structure comprises:
forming an aluminum structure having a plurality of third cavities, each of the plurality of third cavities having a third opening at one side thereof;
spraying a graphene oxide onto at least one of the third cavities of the aluminum structure;
heating the graphene oxide to reduce the graphene oxide to graphene and to form a pre-carbon structure on the aluminum structure; and
removing the aluminum structure from the pre-carbon structure.
16. The method of claim 11 , wherein the joining of the carbon sheet to the pre-carbon structure comprises applying heat or a microwave to the pre-carbon structure and the carbon sheet.
17. The anode layer of claim 1 , wherein the plurality of cavities are regularly spaced.
18. The lithium secondary battery of claim 6 , wherein the plurality of cavities are regularly spaced.