Cathode and method of manufacturing the same
The present application relates to a cathode, a method of manufacturing the same, and a battery including the same. The present application may provide a cathode and a method of manufacturing the same, wherein the cathode comprises an active material layer that contains an acrylic polymer and exhibits excellent resistance to an electrolyte, excellent dispersion of its components and great adhesion to a current collector.
1. A cathode for a secondary battery, comprising:
a current collector; and
an active material layer present on the current collector and comprising an acrylic polymer which forms a cross-linked structure with a polyfunctional cross-linker,
wherein the acrylic polymer comprises a polymerization unit of a (meth)acrylic acid ester compound, a polymerization unit of a monomer containing a cross-linkable functional group, and a polymerization unit of a vinyl-based monomer except for a (meth)acrylic acid ester compound, and
wherein the cross-linkable functional group comprises a hydroxyl group,
wherein the polyfunctional cross-linker is a polyfunctional compound comprising two or more functional groups that contain an isocyanate group,
wherein the polyfunctional compound is an aromatic polyisocyanate,
wherein the polymerization unit of a vinyl-based monomer except for a (meth)acrylic acid ester compound is acrylonitrile,
wherein the acrylic polymer is comprised in the active material layer at a ratio of 0.01 to 10 parts by weight with respect to 100 parts by weight of the active material layer, and
wherein a peel strength of the active material layer to the current collector is 20 gf or greater when measured at a peeling speed of 0.3 m/min and a peeling angle of 180 degrees at room temperature with an electrode specimen sized 15×150 mm 2 .
2. The cathode of claim 1 , wherein the (meth)acrylic acid ester compound is an alkyl (meth)acrylate.
3. The cathode of claim 1 , wherein the acrylic polymer further comprises a polymerization unit of a monomer containing a nitrogen-containing functional group, or a polymerization unit of a monomer containing an alkoxysilane group.
4. The cathode of claim 3 , wherein the acrylic polymer comprises a gel content of 80% to 100%.
5. The cathode of claim 1 , wherein the active material layer further comprises a fluorine-based polymer.
6. The cathode of claim 1 , wherein the active material layer further comprises a cathode active material.
7. The cathode of claim 6 , wherein the cathode active material is comprised in the active material layer at a ratio of 80 to 99.5 parts by weight with respect to 100 parts by weight of the active material layer.
8. The cathode of claim 1 , wherein the active material layer further comprises a conductive material.
9. The cathode of claim 1 , wherein the current collector comprises aluminum.
10. A method of manufacturing the cathode for a secondary battery of claim 1 , the method comprising cross-linking of an acrylic polymer in a state in which a layer of composition forming an active material layer comprising the acrylic polymer is previously formed on a current collector.
11. The method of claim 10 , wherein the acrylic polymer is cross-linked in the range of 50 to 300° C.
12. The method of claim 10 , wherein the acrylic polymer is prepared through solution polymerization using a mixture which comprises a (meth)acrylic acid ester compound, a monomer containing a cross-linkable functional group and a solvent, and a vinyl-based monomer except for the (meth)acrylic acid ester compound.
13. The method of claim 12 , wherein the mixture further comprises a monomer containing a nitrogen-containing functional group or a monomer containing an alkoxysilane group.
14. A secondary battery comprising the cathode of claim 1 .