Positive Electrode For Lithium Secondary Battery And Method For Manufacturing The Same
First Claim
1. A positive electrode for a lithium secondary battery comprising:
- a positive electrode current collector;
a lower positive electrode active material layer disposed on at least one surface of the positive electrode current collector; and
an upper positive electrode active material layer disposed on the lower positive electrode active material layer,wherein the lower positive electrode active material layer comprises 90% or more of a sphere-type carbonaceous conductive material as a conductive material,the upper positive electrode active material layer comprises 90% or more of a needle-type carbonaceous conductive material as a conductive material, anda content of the conductive material contained in the lower positive electrode active material layer is larger than a content of the conductive material contained in the upper positive electrode active material layer.
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Accused Products
Abstract
A positive electrode for a lithium secondary battery includes a positive electrode current collector; a lower positive electrode active material layer disposed on at least one surface of the positive electrode current collector; and an upper positive electrode active material layer disposed on the lower positive electrode active material layer, wherein the lower positive electrode active material layer includes 90% or more of a sphere-type carbonaceous conductive material as a conductive material, the upper positive electrode active material layer includes 90% or more of a needle-type carbonaceous conductive material as a conductive material, and the content of the conductive material contained in the lower positive electrode active material layer is larger than the content of the conductive material contained in the upper positive electrode active material layer.
3 Citations
11 Claims
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1. A positive electrode for a lithium secondary battery comprising:
- a positive electrode current collector;
a lower positive electrode active material layer disposed on at least one surface of the positive electrode current collector; and
an upper positive electrode active material layer disposed on the lower positive electrode active material layer,wherein the lower positive electrode active material layer comprises 90% or more of a sphere-type carbonaceous conductive material as a conductive material, the upper positive electrode active material layer comprises 90% or more of a needle-type carbonaceous conductive material as a conductive material, and a content of the conductive material contained in the lower positive electrode active material layer is larger than a content of the conductive material contained in the upper positive electrode active material layer.
- a positive electrode current collector;
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2. The positive electrode for a lithium secondary battery according to claim 1, wherein the sphere-type carbonaceous conductive material is present in an amount of 1.0-3.0 wt % based on a total weight of the lower positive electrode active material layer.
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3. The positive electrode for a lithium secondary battery according to claim 1, wherein the needle-type carbonaceous conductive material is present in an amount of 0.2-1.0 wt % based on a total weight of the upper positive electrode active material layer.
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4. The positive electrode for a lithium secondary battery according to claim 1, wherein the sphere-type carbonaceous conductive material is carbon black.
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5. The positive electrode for a lithium secondary battery according to claim 1, wherein the needle-type carbonaceous conductive material is carbon nanotubes (CNT), vapor-grown carbon fibers (VGCF), carbon nanofibers (CNF) or a combination of two or more of them.
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6. The positive electrode for a lithium secondary battery according to claim 1, wherein the upper positive electrode active material layer and the lower positive electrode active material layer have a thickness ratio of 90:
- 10-50;
50.
- 10-50;
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7. A method for manufacturing a positive electrode for a lithium secondary battery, comprising:
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dispersing a first positive electrode active material, a first conductive material and a first binder polymer into a solvent to prepare a slurry for a lower positive electrode active material layer; dispersing a second positive electrode active material, a second conductive material and a second binder polymer into a solvent to prepare a slurry for an upper positive electrode active material layer; applying the slurry for a lower positive electrode active material layer to at least one surface of a positive electrode current collector; and further applying the slurry for an upper positive electrode active material layer thereto, before or after the slurry for a lower positive electrode active material layer is dried, wherein the slurry for the lower positive electrode active material layer comprises 90% or more of a sphere-type carbonaceous conductive material as a conductive material, the slurry for upper positive electrode active material layer comprises 90% or more of a needle-type carbonaceous conductive material as a conductive material, and a content of the conductive material contained in the slurry for the lower positive electrode active material layer is larger than a content of the conductive material contained in the slurry for the upper positive electrode active material layer.
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8. A lithium secondary battery comprising the positive electrode for a lithium secondary battery as defined in claim 1.
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9. The positive electrode of claim 1, wherein the sphere-type carbonaceous conductive material has an average diameter (D50) of 15-40 nm.
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10. The positive electrode of claim 9, wherein the needle-type carbonaceous conductive material has an aspect ratio of 100-300.
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11. The positive electrode of claim 6, wherein the thickness ratio is 90:
- 10-70;
30.
- 10-70;
Specification