Binder for secondary battery electrode, secondary battery electrode and secondary battery including same, composition for secondary battery electrode for producing said secondary battery electrode, and method for producing said secondary battery electrode
The present invention provides a binder for a secondary battery electrode, a secondary battery electrode and secondary battery including the same, a composition for a secondary battery electrode for producing the secondary battery electrode, and a method for producing the secondary battery electrode, wherein in the binder for a secondary battery electrode, a copolymer includes a polyvinyl alcohol-derived unit and an ionically substituted acrylate-derived unit, and is cross-linked to each other.
1. A binder for a secondary battery electrode, comprising:
a copolymer, which comprises a polyvinyl alcohol-derived unit and an ionically substituted acrylate-derived unit, the copolymer being cross-linked,
wherein —COOR groups present in the copolymer and a cross-linking agent are bonded by an esterification reaction.
2. The binder for the secondary battery electrode of claim 1 ,
wherein the polyvinyl alcohol-derived unit comprises a unit represented by Formula 1 below:
and
the ionically substituted acrylate-derived unit comprises a unit represented by Formula 2 below:
wherein R is at least one metal cation selected from the group consisting of Na, Li, and K.
3. The binder for the secondary battery electrode of claim 2 ,
wherein the copolymer comprises 2000-3000 units of Formula 1, and comprises 1000-2000 units of Formula 2.
4. The binder for the secondary battery electrode of claim 1 ,
wherein the copolymer comprises the polyvinyl alcohol-derived unit and the ionically substituted acrylate-derived unit at a weight ratio of 6:4 to 8:2.
5. The binder for the secondary battery electrode of claim 1 ,
wherein the ionically substituted acrylate is at least one of a salt selected from the group consisting of sodium acrylate and lithium acrylate.
6. The binder for the secondary battery electrode of claim 1 ,
wherein the copolymer is a block copolymer comprising the polyvinyl alcohol-derived unit and the ionically substituted acrylate-derived unit.
7. The binder for the secondary battery electrode of claim 1 ,
wherein the copolymer has a weight average molecular weight of 100,000 Da to 500,000 Da.
8. The binder for the secondary battery electrode of claim 1 ,
wherein the binder comprises an ester.
9. The binder for the secondary battery electrode of claim 1 ,
wherein in the copolymer,
a molar fraction of the ionically substituted acrylate-derived unit among all units, excluding the polyvinyl alcohol-derived unit, is 98 mol % to 100 mol %.
10. A secondary battery electrode comprising:
an electrode active material;
a conductive material; and
the binder according to claim 1 .
11. The secondary battery electrode of claim 10 ,
wherein the electrode active material further comprises a Si-based material.
12. A secondary battery comprising:
a positive electrode;
a negative electrode according to claim 10 ;
a separator interposed between the positive electrode and negative electrode; and
an electrolyte solution.