KR-20260065673-A - CATHODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

KR20260065673AKR 20260065673 AKR20260065673 AKR 20260065673AKR-20260065673-A

Abstract

A positive electrode for a lithium secondary battery according to one embodiment of the present disclosure comprises a positive electrode current collector; and a positive electrode composite layer on at least one surface of the positive electrode current collector, wherein the positive electrode composite layer comprises a first positive electrode composite layer on the positive electrode current collector; and a second positive electrode composite layer on the first positive electrode composite layer, wherein the first positive electrode composite layer and the second positive electrode composite layer each independently comprise a lithium metal phosphate and a lithium transition metal oxide as active materials, wherein the weight of the lithium metal phosphate included in the first positive electrode composite layer is greater than the weight of the lithium transition metal oxide, wherein the first positive electrode composite layer comprises a point-shaped conductive material, and the second positive electrode composite layer comprises a linear conductive material.

Inventors

김재람
배지희
송연화
연정석

Assignees

에스케이온 주식회사

Dates

Publication Date: 20260511
Application Date: 20241101

Claims (11)

A positive electrode for a lithium secondary battery comprising: a positive current collector; and a positive composite layer on at least one surface of the positive current collector, The above anode composite layer comprises a first anode composite layer on an anode current collector; and a second anode composite layer on the first anode composite layer. The first anode composite layer and the second anode composite layer each independently comprise lithium metal phosphate and lithium transition metal oxide as active materials, and The weight of the lithium metal phosphate included in the first anode composite layer is greater than the weight of the lithium transition metal oxide, and The above first anode composite layer includes a point-shaped conductive material, and The above second anode composite layer comprises a linear conductive material, Cathode for lithium secondary batteries.
In paragraph 1, The content of the point-shaped conductive material included in the first anode composite layer is 0.3 weight% to 0.5 weight%, Cathode for lithium secondary batteries.
In paragraph 1, The content of the linear conductive material included in the second anode composite layer is 0.5 weight% to 1.5 weight%, Cathode for lithium secondary batteries.
In paragraph 1, The above first anode composite layer further comprises a linear conductive material, Cathode for lithium secondary batteries.
In paragraph 1, The above second anode composite layer does not include a dot-shaped conductive material, Cathode for lithium secondary batteries.
In paragraph 4, The weight of the linear conductive material included in the first anode composite layer is less than or equal to the weight of the linear conductive material included in the second anode composite layer. Cathode for lithium secondary batteries.
In paragraph 4, The content of the linear conductive material included in the first anode composite layer is 0.5 weight% to 0.7 weight%, Cathode for lithium secondary batteries.
In paragraph 1, The above second anode composite layer further includes a dot-shaped conductive material, and The content of the dot-shaped conductive material included in the second anode composite layer is 0.1 weight% to 0.5 weight%, Cathode for lithium secondary batteries.
In paragraph 1, The above point-shaped conductive material includes carbon black, Cathode for lithium secondary batteries.
In paragraph 1, The above linear conductive material comprises carbon nanotubes (CNT), Cathode for lithium secondary batteries.
A positive electrode for a lithium secondary battery according to any one of claims 1 to 10, Lithium secondary battery.

Description

Cathode for lithium secondary battery and lithium secondary battery including the same The present disclosure relates to a positive electrode for a lithium secondary battery and a lithium secondary battery including the same. Recently, extensive research is being conducted on electric vehicles (EVs) that can replace fossil fuel-using vehicles, such as gasoline and diesel cars, which are one of the major causes of air pollution. Lithium-ion batteries, which possess high discharge voltage and output stability, are primarily used as the power source for these EVs. To improve the performance of the above-mentioned lithium secondary battery, it is necessary to develop technology capable of improving the energy density and safety of the cathode for the lithium secondary battery. FIG. 1 is a conceptual cross-sectional view of a positive electrode for a lithium secondary battery according to one embodiment. Hereinafter, the technology disclosed in this specification and its embodiments are described in detail with reference to the attached drawings. However, the embodiments of the technology may be modified in various different forms, and their scope is not limited to the embodiments described below. Furthermore, the technology disclosed in this specification may not only be applied in a limited manner to the configurations of the embodiments described below, but may also be configured by selectively combining all or part of each embodiment to allow for various modifications. As the demand for lithium-ion batteries increases, there is a growing need for technology capable of manufacturing cathodes with superior performance. In this regard, NCM cells utilizing NCM (lithium nickel-cobalt-manganese oxide) active materials as the cathode exhibit excellent energy density but suffer from the disadvantages of relatively poor safety and high production costs. Conversely, cells utilizing lithium-phosphate active materials with olivine structures, such as LFP (lithium iron phosphate), offer superior safety and price competitiveness but suffer from the disadvantages of relatively lower energy density and poor low-temperature performance. According to one embodiment of the present disclosure, the aforementioned problems can be mitigated to provide a cathode for a lithium secondary battery with excellent energy density, safety, lifespan performance, and price competitiveness. Hereinafter, embodiments of the present disclosure will be described in detail with reference to FIG. 1. FIG. 1 is a conceptual cross-sectional view of a positive electrode for a lithium secondary battery according to one embodiment. cathode for lithium secondary batteries A positive electrode (100) for a lithium secondary battery according to one embodiment comprises a positive electrode current collector (10); and a positive electrode composite layer (20) on at least one surface of the positive electrode current collector, wherein the positive electrode composite layer comprises a first positive electrode composite layer (21) on the positive electrode current collector (10); and a second positive electrode composite layer (22) on the first positive electrode composite layer. The first positive electrode composite layer (21) and the second positive electrode composite layer (22) each independently comprise lithium metal phosphate and lithium transition metal oxide as active materials, wherein the weight of the lithium metal phosphate included in the first positive electrode composite layer (21) exceeds the weight of the lithium transition metal oxide, the first positive electrode composite layer (21) comprises a point-shaped conductive material, and the second positive electrode composite layer (22) comprises a linear conductive material. The above lithium transition metal oxide may include an active material such as NCM (lithium nickel-cobalt-manganese oxide) having excellent energy density, and the above lithium metal phosphate may include an active material such as LFP (lithium iron phosphate) as an active material having an olivine structure having excellent structural stability. The above-mentioned positive electrode (100) for a lithium secondary battery has a multilayer structure comprising a mixture of lithium transition metal oxide and lithium metal phosphate as active materials (see FIG. 1), which can contribute to further cell performance improvement by mutually compensating for the disadvantages of each active material while maximizing their advantages. The composition of the positive current collector (10) is not particularly limited. For example, the positive current collector may be a plate or foil made of one or more of indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and alloys thereof. In some embodiments, the positive current collector may be aluminum foil (Al-foil). The thickness of the anode current collector (10) is no