KR-20260065235-A - CATHODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

KR20260065235AKR 20260065235 AKR20260065235 AKR 20260065235AKR-20260065235-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 as an active material, and at least one of the first positive electrode composite layer and the second positive electrode composite layer comprises a lithium transition metal oxide as an active material, and the weight of the lithium metal phosphate included in the first positive electrode composite layer is greater than or equal to the weight of the lithium metal phosphate included in the second positive electrode composite layer.

Inventors

배지희
김재람
송연화
연정석

Assignees

에스케이온 주식회사

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

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 include lithium metal phosphate as an active material, and At least one of the first anode composite layer and the second anode composite layer comprises a lithium transition metal oxide as an active material, and The weight of the lithium metal phosphate included in the first anode composite layer is greater than or equal to the weight of the lithium metal phosphate included in the second anode composite layer. Cathode for lithium secondary batteries.
In paragraph 1, When the first anode composite layer comprises a lithium transition metal oxide, the weight of the lithium metal phosphate included in the first anode composite layer is greater than or equal to the weight of the lithium transition metal oxide included in the first anode composite layer. Cathode for lithium secondary batteries.
In paragraph 2, The weight ratio of lithium metal phosphate and lithium transition metal oxide included in the first anode composite layer is 70:30 to 99:1, Cathode for lithium secondary batteries.
In paragraph 1, When the second anode composite layer comprises a lithium transition metal oxide, the weight ratio of the lithium metal phosphate and the lithium transition metal oxide included in the second anode composite layer is 30:70 to 70:30. Cathode for lithium secondary batteries.
In paragraph 1, The total weight of the lithium metal phosphate included in the anode composite layer is greater than or equal to the total weight of the lithium transition metal oxide included in the anode composite layer. Cathode for lithium secondary batteries.
In paragraph 5, The weight ratio of lithium metal phosphate and lithium transition metal oxide included in the above anode composite layer is 60:40 to 80:20, Cathode for lithium secondary batteries.
In paragraph 1, The loading weight (LW) ratio of the first anode composite layer and the second anode composite layer is 30:70 to 70:30, Cathode for lithium secondary batteries.
In paragraph 1, The above lithium metal phosphate is a lithium manganese-iron phosphate (LMFP)-based active material represented by the chemical formula LiMn x Fe 1-x PO 4 (0<x<1), Cathode for lithium secondary batteries.
In paragraph 1, The above lithium transition metal oxide has a single particle form, Cathode for lithium secondary batteries.
A positive electrode for a lithium secondary battery according to any one of claims 1 to 9, 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 a lithium metal phosphate as an active material, and at least one of the first positive electrode composite layer (21) and the second positive electrode composite layer (22) comprises a lithium transition metal oxide as an active material, and the weight of the lithium metal phosphate included in the first positive electrode composite layer (21) is greater than or equal to the weight of the lithium metal phosphate included in the second positive electrode composite layer (22). 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 positive electrode (100) for the lithium secondary battery has a multilayer structure including both lithium transition metal oxide and lithium metal phosphate as active materials (see FIG. 1), so that the disadvantages of each active material are mutually compensated for while the advantages are maximized, and it can contribute to further improvement of cell performance. The composition of the positive electrode current collector (10) is not particularly limited. For example, the positive electrode 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 electrode current collector may be aluminum foil (Al-