Granted Patent B2

US 12,322,792 · App. 18/746,065 · Granted Jun 3, 2025

Inventors: Su Ung Chae (Daejeon, KR); Seung Ryul Choi (Daejeon, KR)

Assignee: SK ON CO., LTD.

H01M4/366H01M4/131H01M4/136H01M4/525H01M4/5825H01M4/625H01M10/0525H01M2004/021H01M2004/028

Abstract

Claims (27)

1. A cathode comprising:

a current collector;

a first cathode mixture layer on at least one surface of the current collector; and

a second cathode mixture layer on the first cathode mixture layer,

wherein the first cathode mixture layer includes a first cathode active material having a layered crystal structure,

wherein the second cathode mixture layer includes the first active material and a second cathode active material having an olivine-based crystal structure,

wherein the first cathode mixture layer and the second cathode mixture layer have a thickness ratio of 1:9 to 4:6, and

wherein a content of the second cathode active material, included in a cathode mixture layer including the first cathode mixture layer and the second cathode mixture layer, is 50 wt % or more with respect to a total weight of a cathode active material including the first cathode active material and the second cathode active material.

2. The cathode of claim 1 , wherein the first cathode active material is a lithium transition metal composite oxide represented by Formula 1:

LiaNixCoyMnzM1wO2  [Formula 1]

In Formula 1 above, M1 is at least one selected from the group consisting of Al, Mg, V, Ti, and Zr, and

0.9≤a≤1.5, 0.5≤x<1, 0<y≤0.4, 0<z≤0.4, 0<w≤0.04, and x+y+z+w=1 are satisfied.

3. The cathode of claim 1 , wherein the second cathode active material is a lithium transition metal oxide represented by Formula 2:

LiMPO4  [Formula 2]

In Formula 2, M is at least one selected from the group consisting of Fe, Mn, Ni, Co, and V.

4. The cathode of claim 1 , wherein the second cathode mixture layer includes 0.5 to 30 wt % of the first cathode active material with respect to a total weight of a cathode active material including the first cathode active material and the second cathode active material in a cathode mixture layer including the first cathode mixture layer and the second cathode mixture layer.

5. The cathode of claim 1 , wherein the second cathode mixture layer includes a linear conductive agent having an aspect ratio of 2 or more.

6. The cathode of claim 5 , wherein the linear conductive agent is included in an amount of 1 to 10 wt % with respect to a total weight of a second cathode mixture layer.

7. The cathode of claim 1 , wherein the second cathode mixture layer includes a linear conductive agent of at least one metal fiber selected from the group consisting of a carbon nanotube, a carbon fiber, copper, nickel, aluminum, and silver.

8. The cathode of claim 1 , wherein the first cathode mixture layer further includes at least one conductive agent selected from the group consisting of a carbon fiber, a carbon nanotube, graphite, carbon black, a metal fiber, a metal powder, a conductive whisker, a conductive metal oxide, and a conductive polymer.

9. The cathode of claim 8 , wherein the conductive agent is included in an amount of 1 to 10 wt % with respect to a total weight of the first cathode mixture layer.

10. The cathode of claim 1 , wherein at least one of the first and second cathode mixture layers further includes a third cathode active material other than the first and second cathode active materials.

11. The cathode of claim 10 , wherein the third cathode active material is at least one selected from the group consisting of Li2MnO3, Li2PtO3, LiMn2O4, and LiNi0.5Mn1.5O4.

12. A lithium secondary battery, wherein

an anode and a cathode are alternately stacked,

a separator is interposed between the anode and the cathode, and

the cathode is the cathode of claim 1 .

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (12)