CN-122000314-A - Positive electrode for lithium secondary battery and lithium secondary battery comprising same

CN122000314ACN 122000314 ACN122000314 ACN 122000314ACN-122000314-A

Abstract

A positive electrode for a lithium secondary battery according to a specific embodiment of the present invention includes a positive electrode current collector and a positive electrode mixture layer on at least one side of the positive electrode current collector, wherein the positive electrode mixture layer includes a first positive electrode mixture layer on the positive electrode current collector and a second positive electrode mixture layer on the first positive electrode mixture layer, each of the first positive electrode mixture layer and the second positive electrode mixture layer independently includes lithium metal phosphorus oxide as an active material, at least one of the first positive electrode mixture layer and the second positive electrode mixture layer includes lithium transition metal oxide as an active material, and a weight of lithium metal phosphorus oxide included in the first positive electrode mixture layer is greater than or equal to a weight of lithium metal phosphorus oxide included in the second positive electrode mixture layer.

Inventors

Pei Zhixi
Jin Zailan
SONG YANHE
Yan Qingxi

Assignees

SK新能源株式会社

Dates

Publication Date: 20260508
Application Date: 20250928
Priority Date: 20241101

Claims (10)

1. A positive electrode for a lithium secondary battery comprising a positive electrode current collector and a positive electrode mixture layer on at least one surface of the positive electrode current collector, Wherein the positive electrode mixture layer comprises a first positive electrode mixture layer on a positive electrode current collector and a second positive electrode mixture layer on the first positive electrode mixture layer, The first positive electrode mixture layer and the second positive electrode mixture layer each independently contain lithium metal phosphorus oxide as an active material, At least one of the first positive electrode mixture layer and the second positive electrode mixture layer contains a lithium transition metal oxide as an active material, The weight of lithium metal phosphorus oxide contained in the first positive electrode mixture layer is greater than or equal to the weight of lithium metal phosphorus oxide contained in the second positive electrode mixture layer.
2. The positive electrode for a lithium secondary battery according to claim 1, wherein when the first positive electrode mixture layer contains a lithium transition metal oxide, the weight of lithium metal phosphorus oxide contained in the first positive electrode mixture layer is greater than or equal to the weight of lithium transition metal oxide contained in the first positive electrode mixture layer.
3. The positive electrode for a lithium secondary battery according to claim 2, wherein a weight ratio of lithium metal phosphorus oxide to lithium transition metal oxide contained in the first positive electrode mixture layer is 70:30 to 99:1.
4. The positive electrode for a lithium secondary battery according to claim 1, wherein, when the second positive electrode mixture layer contains a lithium transition metal oxide, a weight ratio of lithium metal phosphorus oxide to lithium transition metal oxide contained in the second positive electrode mixture layer is 30:70 to 70:30.
5. The positive electrode for a lithium secondary battery according to claim 1, wherein a total weight of lithium metal phosphorus oxide contained in the positive electrode mixture layer is greater than or equal to a total weight of lithium transition metal oxide contained in the positive electrode mixture layer.
6. The positive electrode for a lithium secondary battery according to claim 5, wherein a weight ratio of lithium metal phosphorus oxide to lithium transition metal oxide contained in the positive electrode mixture layer is 60:40 to 80:20.
7. The positive electrode for a lithium secondary battery according to claim 1, wherein a Load Weight (LW) ratio of the first positive electrode mixture layer to the second positive electrode mixture layer is 30:70 to 70:30.
8. The positive electrode for a lithium secondary battery according to claim 1, wherein the lithium metal phosphorus oxide is a lithium iron manganese phosphate (LMFP) based active material represented by the chemical formula LiMn x Fe 1-x PO 4 , wherein 0< x <1.
9. The positive electrode for a lithium secondary battery according to claim 1, wherein the lithium transition metal oxide has a single particle form.
10. A lithium secondary battery comprising the positive electrode for a lithium secondary battery according to any one of claims 1 to 9.

Description

Positive electrode for lithium secondary battery and lithium secondary battery comprising same Technical Field The present invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery including the same. Background In recent years, there have been a great deal of research into Electric Vehicles (EVs) that can replace vehicles using fossil fuel, such as gasoline vehicles and diesel vehicles, which are one of the main causes of atmospheric pollution, and as a power source of such Electric Vehicles (EVs), lithium secondary batteries having high discharge voltage and high power stability have been mainly used. In order to improve the performance of the lithium secondary battery, it is necessary to develop a technique capable of improving the energy density, safety, and the like of the positive electrode for the lithium secondary battery. Disclosure of Invention First, the technical problem to be solved According to an aspect of the present invention, a positive electrode for a lithium secondary battery having improved safety may be provided. According to another aspect of the present invention, the energy density of the positive electrode for a lithium secondary battery can be improved. According to another aspect of the present invention, the life performance of the positive electrode for a lithium secondary battery can be improved. (II) technical scheme The positive electrode for a lithium secondary battery according to one specific embodiment includes a positive electrode current collector and a positive electrode mixture layer on at least one side of the positive electrode current collector, wherein the positive electrode mixture layer includes a first positive electrode mixture layer on the positive electrode current collector and a second positive electrode mixture layer on the first positive electrode mixture layer, each of the first positive electrode mixture layer and the second positive electrode mixture layer independently includes lithium metal phosphorus oxide as an active material, at least one of the first positive electrode mixture layer and the second positive electrode mixture layer includes lithium transition metal oxide as an active material, and a weight of lithium metal phosphorus oxide included in the first positive electrode mixture layer is greater than or equal to a weight of lithium metal phosphorus oxide included in the second positive electrode mixture layer. In some embodiments, when the first positive electrode mixture layer includes lithium transition metal oxide, the weight of lithium metal phosphorus oxide included in the first positive electrode mixture layer may be greater than or equal to the weight of lithium transition metal oxide included in the first positive electrode mixture layer. In some embodiments, the weight ratio of lithium metal phosphorus oxide to lithium transition metal oxide included in the first positive electrode mixture layer may be 70:30 to 99:1. In some embodiments, when the second positive electrode mixture layer includes a lithium transition metal oxide, a weight ratio of lithium metal phosphorus oxide to lithium transition metal oxide included in the second positive electrode mixture layer may be 30:70 to 70:30. In some embodiments, the total weight of lithium metal phosphorus oxide contained in the positive electrode mixture layer may be greater than or equal to the total weight of lithium transition metal oxide contained in the positive electrode mixture layer. In some embodiments, the weight ratio of lithium metal phosphorus oxide to lithium transition metal oxide included in the positive electrode mixture layer may be 60:40 to 80:20. In some embodiments, the first positive electrode mixture layer and the second positive electrode mixture layer may have a Load Weight (LW) ratio of 30:70 to 70:30. In some embodiments, the lithium metal phosphorus oxide may be a lithium manganese iron phosphate (LMFP) based active substance represented by the chemical formula LiMn xFe1-xPO4 (0 < x < 1). In some embodiments, the lithium transition metal oxide may have a single particle form. A lithium secondary battery according to one embodiment includes the positive electrode for a lithium secondary battery according to any one of the above embodiments. (III) beneficial effects According to one embodiment of the present invention, the stability of the positive electrode for a lithium secondary battery can be improved. According to another embodiment of the present invention, a positive electrode for a lithium secondary battery having a high energy density may be provided. According to another embodiment of the present invention, a positive electrode for a lithium secondary battery having excellent life performance can be provided. Drawings Fig. 1 is a sectional view conceptually showing a positive electrode for a lithium secondary battery according to one specific embodiment. Description of the reference numerals: 100 po