US-20260128285-A1 - CATHODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY INCLUDING THE SAME

US20260128285A1US 20260128285 A1US20260128285 A1US 20260128285A1US-20260128285-A1

Abstract

A cathode for a lithium secondary battery according to an embodiment of the present disclosure includes: a cathode current collector; and a cathode mixture layer on at least one surface of the cathode current collector, and 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, each of the first cathode mixture layer and the second cathode mixture layer independently includes a lithium metal phosphate as an active material, at least one of the first cathode mixture layer and the second cathode mixture layer includes a lithium transition metal oxide as an active material, and a weight of the lithium metal phosphate included in the first cathode mixture layer is greater than or equal to a weight of the lithium metal phosphate included in the second cathode mixture layer.

Inventors

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

Assignees

SK ON CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20250925
Priority Date: 20241101

Claims (10)

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

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This patent document claims the priority and benefits of Korean Patent Application No. 10-2024-0153380 filed on Nov. 1, 2024, the disclosure of which is incorporated herein by reference in its entirety. TECHNICAL FIELD The disclosure and implementations disclosed in this patent document generally relate to a cathode for a lithium secondary battery and a lithium secondary battery including the same. BACKGROUND Recently, extensive research has been conducted on electric vehicles (EV) that may replace fossil fuel-powered vehicles, such as gasoline and diesel vehicles, which are one of the main causes of air pollution, and a lithium secondary battery, with high discharge voltage and power stability, may be primarily used as a power source for such EVs. To enhance the performance of a lithium secondary battery, the development of technologies that may improve the energy density and safety of such a lithium secondary battery is essential. SUMMARY According to an aspect of the present disclosure, a cathode for a lithium secondary battery having improved safety may be provided. According to another aspect of the present disclosure, the energy density of a cathode for a lithium secondary battery may be improved. According to another aspect of the present disclosure, the lifespan performance of a cathode for a lithium secondary battery may be improved. A cathode for a lithium secondary battery according to an embodiment may include: a cathode current collector; and a cathode mixture layer on at least one surface of the cathode current collector, and the cathode mixture layer may include: a first cathode mixture layer on the cathode current collector; and a second cathode mixture layer on the first cathode mixture layer, each of the first cathode mixture layer and the second cathode mixture layer may independently include a lithium metal phosphate as an active material, at least one of the first cathode mixture layer and the second cathode mixture layer may include a lithium transition metal oxide as an active material, and a weight of the lithium metal phosphate included in the first cathode mixture layer may be greater than or equal to a weight of the lithium metal phosphate included in the second cathode mixture layer. In some embodiments, when the first cathode mixture layer includes a lithium transition metal oxide, a weight of the lithium metal phosphate included in the first cathode mixture layer may be greater than or equal to a weight of the lithium transition metal oxide included in the first cathode mixture layer. In some embodiments, a weight ratio of the lithium metal phosphate and the lithium transition metal oxide included in the first cathode mixture layer may be 70:30 to 99:1. In some embodiments, when the second cathode mixture layer includes a lithium transition metal oxide, a weight ratio of the lithium metal phosphate and the lithium transition metal oxide included in the second cathode mixture layer is 30:70 to 70:30. In some embodiments, a total weight of the lithium metal phosphate included in the cathode mixture layer may be greater than or equal to a total weight of the lithium transition metal oxide included in the cathode mixture layer. In some embodiments, a weight ratio of the lithium metal phosphate and the lithium transition metal oxide included in the cathode mixture layer may be 60:40 to 80:20. In some embodiments, a loading weight (LW) ratio of the first cathode mixture layer and the second cathode mixture layer is 30:70 to 70:30. In some embodiments, the lithium metal phosphate may be a lithium manganese iron phosphate (LMFP)-based active material represented by a chemical formula, LiMnxFe1-xPO4 (0<x<1). In some embodiments, the lithium transition metal oxide may have a single particle form. A lithium secondary battery according to an embodiment may include the cathode for a lithium secondary battery in the above-described embodiments. According to an embodiment of the present disclosure, the safety of a cathode for a lithium secondary battery may be improved. According to another embodiment of the present disclosure, a cathode for a lithium secondary battery having high-energy density may be provided. According to another embodiment of the present disclosure, a cathode for a lithium secondary battery having excellent lifespan performance may be provided. BRIEF DESCRIPTION OF DRAWINGS Certain aspects, features, and advantages of the present disclosure are 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 specification and embodiments thereof will be described in detail with reference to the accompanying drawings. However, the embodiments of the technology may be modified in various other forms, and the sc