US-20260128286-A1 - CATHODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

Abstract

A cathode for a lithium secondary battery includes a cathode current collector; and a cathode mixture layer on at least one surface of the cathode current collector, wherein the cathode mixture layer includes a first cathode mixture layer on the cathode current collector; and a second cathode mixture layer on the first cathode mixture layer, the first cathode mixture layer and the second cathode mixture layer respectively independently include lithium metal phosphate and lithium transition metal oxide as active materials, a weight of the lithium metal phosphate included in the first cathode mixture layer exceeds a weight of the lithium transition metal oxide, the first cathode mixture layer includes a spherical-type conductive material, and the second cathode mixture a needle-type layer includes conductive material.

Inventors

• Jae Ram Kim
• Ji Hee Bae
• Yeon Hwa SONG
• Jeong Seok YEON

Assignees

• SK ON CO., LTD.

Dates

Publication Date

20260507

Application Date

20251023

Priority Date

20241101

Claims (11)

1. 1 . A cathode for a lithium secondary battery including a cathode current collector; and a cathode mixture layer on at least one surface of the cathode current collector, wherein the cathode mixture layer includes a first cathode mixture layer on the cathode current collector; and a second cathode mixture layer on the first cathode mixture layer, the first cathode mixture layer and the second cathode mixture layer respectively independently include lithium metal phosphate and lithium transition metal oxide as active materials, a weight of the lithium metal phosphate included in the first cathode mixture layer exceeds a weight of the lithium transition metal oxide, the first cathode mixture layer includes a spherical-type conductive material, and the second cathode mixture layer includes a needle-type conductive material.
2. 2 . The cathode for a lithium secondary battery of claim 1 , wherein a content of the spherical-type conductive material included in the first cathode mixture layer is 0.3 wt % to 0.5 wt %.
3. 3 . The cathode for a lithium secondary battery of claim 1 , wherein a content of the needle-type conductive material included in the second cathode mixture layer is 0.5 wt % to 1.5 wt %.
4. 4 . The cathode for a lithium secondary battery of claim 1 , wherein the first cathode mixture layer further comprises a needle-type conductive material.
5. 5 . The cathode for a lithium secondary battery of claim 1 , wherein the second cathode mixture layer does not include a spherical-type conductive material.
6. 6 . The cathode for a lithium secondary battery of claim 4 , wherein the weight of the needle-type conductive material included in the first cathode mixture layer is less than or equal to the weight of the needle-type conductive material included in the second cathode mixture layer.
7. 7 . The cathode for a lithium secondary battery of claim 4 , wherein the content of the needle-type conductive material included in the first cathode mixture layer is 0.5 wt % to 0.7 wt %.
8. 8 . The cathode for a lithium secondary battery of claim 1 , wherein the second cathode mixture layer further comprises a spherical-type conductive material, and the content of the spherical-type conductive material included in the second cathode mixture layer is 0.1 wt % to 0.5 wt %.
9. 9 . The cathode for a lithium secondary battery of claim 1 , wherein the spherical-type conductive material comprises carbon black.
10. 10 . The cathode for a lithium secondary battery of claim 1 , wherein the needle-type conductive material comprises carbon nanotubes (CNT).
11. 11 . A lithium secondary battery, comprising: the cathode for a lithium secondary battery of claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This patent document claims the priority and benefits of Korean Patent Application No. 10-2024-0153381 filed on Nov. 1, 2024, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to a cathode for a lithium secondary battery and a lithium secondary battery including the same. BACKGROUND Recently, research on an electric vehicle (EV) that may replace a vehicle using a fossil fuel, such as a gasoline vehicle and a diesel vehicle, which is one of the main causes of air pollution, is being actively conducted, and a lithium secondary battery with high discharge voltage and output stability is mainly used as a power source for such an electric vehicle (EV). In order to improve the performance of the lithium secondary battery, it is necessary to develop a technology that can improve energy density and safety of a cathode for the lithium secondary battery. SUMMARY According to an aspect of the present disclosure, a cathode for a lithium secondary battery with improved safety may be provided. According to another aspect of the present disclosure, energy density of a cathode for a lithium secondary battery may be improved. According to another aspect of the present disclosure, lifespan performance of a cathode for a lithium secondary battery may be improved. According to an aspect of the present disclosure, a cathode for a lithium secondary battery includes a cathode current collector; and a cathode mixture layer on at least one surface of the cathode current collector, wherein the cathode mixture layer includes a first cathode mixture layer on the cathode current collector; and a second cathode mixture layer on the first cathode mixture layer, wherein the first cathode mixture layer and the second cathode mixture layer respectively independently include lithium metal phosphate and lithium transition metal oxide as active materials, a weight of the lithium metal phosphate included in the first cathode mixture layer exceeds a weight of the lithium transition metal oxide, and the first cathode mixture layer includes a spherical-type conductive material, and the second cathode mixture layer includes a needle-type conductive material. In some embodiments, a content of the spherical-type conductive material included in the first cathode mixture layer may be 0.1 wt % to 0.5 wt %. In some embodiments, a content of the needle-type conductive material included in the second cathode mixture layer may be 0.5 wt % to 1.5 wt %. In some embodiments, the first cathode mixture layer may further include a needle-type conductive material. In some embodiments, the second cathode mixture layer may not include a spherical-type conductive material. In some embodiments, the weight of the needle-type conductive material included in the first cathode mixture layer may be less than or equal to the weight of the needle-type conductive material included in the second cathode mixture layer. In some embodiments, the content of the needle-type conductive material included in the first cathode mixture layer may be 0.5 wt % to 0.7 wt %. In some embodiments, the second cathode mixture layer may further include a spherical-type conductive material, and the content of the spherical-type conductive material included in the second cathode mixture layer may be 0.3 wt % to 0.5 wt %. In some embodiments, the spherical-type conductive material may include carbon black. In some embodiments, the needle-type conductive material may include carbon nanotubes (CNT). A lithium secondary battery according to an embodiment includes the cathode for a lithium secondary battery of any one of the above-described embodiments. BRIEF DESCRIPTION OF DRAWINGS Certain aspects, features, and advantages of the disclosed technology may be illustrated by the following detailed description with reference to the accompanying drawings. FIG. 1 is a cross-sectional view conceptually illustrating a cathode for a lithium secondary battery according to an embodiment. DETAILED DESCRIPTION Hereinafter, the technology disclosed in this present specification and embodiments thereof will be described in detail with reference to the attached drawings. However, the embodiments of the technology may be modified in various different forms, and the scope thereof is not limited to the embodiments described below. In addition, the technology disclosed in this specification may be applied not only by being limited to the configurations of the embodiments described below, but also may be configured by selectively combining all or part of each embodiment so that various modifications may be made. As demand for a lithium secondary battery increases, a technology that can manufacture a cathode having excellent performance is required. Related thereto, in the case of an NCM cell using a lithium nickel-cobalt-manganese oxide (NCM) as a cathode active material, the NCM cell has excellent energy den