Binder composition for rechargeable lithium battery, preparing method of same, and rechargeable lithium battery including binder composition

1. A binder composition for a rechargeable lithium battery, the binder composition comprising:

a semi-interpenetrating polymer network (semi-IPN) including:

a copolymer having a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2; and

polyacrylamide,

wherein,

R 1 and R 2 are the same or different and are independently selected from hydrogen, or a substituted or unsubstituted C1 to C10 alkyl group, and

R 3 and R 4 are an alkali metal, and

wherein,

R 5 to R 8 are the same or different, and are independently hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a substituted or unsubstituted C1 to C30 alkoxy group.

2. The binder composition for a rechargeable lithium battery as claimed in claim 1 , wherein:

the repeating unit represented by Chemical Formula 1 is included in an amount of about 40 mol % to about 90 mol % based on a total amount of the copolymer, and

the repeating unit represented by the above Chemical Formula 2 is included in an amount of about 10 mol % to about 60 mol % based on a total amount of the copolymer.

3. The binder composition for a rechargeable lithium battery as claimed in claim 1 , wherein a mole ratio of the copolymer to the polyacrylamide ranges from about 1:9 to about 5:5.

4. The binder composition for a rechargeable lithium battery as claimed in claim 1 , wherein the binder composition further comprises a free alkali metal ion.

5. The binder composition for a rechargeable lithium battery as claimed in claim 4 , wherein the free alkali metal ion is included in an amount of about 1 part by mole to about 10 parts by mole based on 100 parts by mole of a sum of the copolymer and the polyacrylamide.

6. The binder composition for a rechargeable lithium battery of claim 1 , wherein the binder composition for a rechargeable lithium battery further comprises an alkali metal ion and a phosphorus (P)-based compound.

7. The binder composition for a rechargeable lithium battery as claimed in claim 6 , wherein the phosphorus-based compound is a phosphorus-containing anion.

8. The binder composition for a rechargeable lithium battery as claimed in claim 6 , wherein the alkali metal ion and the phosphorus-based compound are adsorbed on the semi interpenetrating polymer network.

9. The binder composition for a rechargeable lithium battery as claimed in claim 6 , wherein the phosphorus-based compound is included in an amount of about 1 part by mole to about 10 parts by mole based on 100 parts by mole of a sum of the copolymer and the polyacrylamide.

10. The binder composition for a rechargeable lithium battery as claimed in claim 6 , wherein the binder composition for a rechargeable lithium battery further comprises polyalkylene glycol.

11. The binder composition for a rechargeable lithium battery as claimed in claim 10 , wherein the polyalkylene glycol is included in an amount of about 5 mol % to about 50 mol % based on a sum of copolymer, the polyacrylamide, and the polyalkylene glycol.

12. The binder composition for a rechargeable lithium battery as claimed in claim 10 , wherein the polyalkylene glycol has a weight-average molecular weight of about 400 g/mol to about 10,000 g/mol.

13. The binder composition for a rechargeable lithium battery as claimed in claim 1 , wherein the binder composition has a pH of about 6 to about 11.

14. The binder composition for a rechargeable lithium battery as claimed in claim 1 , wherein a viscosity of the binder composition ranges from about 10,000 cps to about 100,000 cps.

15. A rechargeable lithium battery, comprising:

an electrode including the binder composition according to claim 1 , and an electrode active material; and

an electrolyte.

16. The rechargeable lithium battery as claimed in claim 15 , wherein the electrode active material includes Si, SiOx, a Si—C composite, a Si-Q alloy, graphite, or a combination thereof, wherein x in SiOx is in the range of 0<x<2, and Q in Si-Q is an alkali metal, an alkaline-earth metal, a Group 13 to 16 element, a transition element, a rare earth element, or a combination thereof, but is not Si.

17. A method of manufacturing a binder composition for a rechargeable lithium battery, the method comprising:

preparing a copolymer of at least one monomer selected from an olefin-based monomer, an aromatic vinyl monomer, and an alkyl vinyl ether monomer, and a cyclic unsaturated acid anhydride monomer,

adding an alkali metal-containing compound to a solution including the copolymer; and

adding an acrylamide monomer to the solution to perform polymerization such that a semi-interpenetrating network structure of the copolymer and polyacrylamide is formed, wherein:

the at least one monomer selected from an olefin-based monomer, an aromatic vinyl monomer, and an alkyl vinyl ether monomer and the cyclic unsaturated acid anhydride monomer are selected such that the copolymer has a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2,

wherein,

R 1 and R 2 are the same or different and are independently selected from hydrogen, or a substituted or unsubstituted C1 to C10 alkyl group, and

R 3 and R 4 are an alkali metal, and

wherein,

R 5 to R 8 are the same or different, and are independently hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, or a substituted or unsubstituted C1 to C30 alkoxy group.

18. The method as claimed in claim 17 , further comprising adding the alkali metal compound to the semi-interpenetrating network structure after forming the semi-interpenetrating network structure.

19. The method as claimed in claim 17 , further comprising adding polyalkylene glycol to the solution including the copolymer after preparing the copolymer.