Positive electrode active material and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2025002367-A1
Application number	US-202318527866-A
Country	US
Kind code	A1
Filing date	Dec 4, 2023
Priority date	Jun 28, 2023
Publication date	Jan 2, 2025
Grant date	—

Abstract

In an embodiment, a cathode active material can include a lithium oxide having a disordered rocksalt (DRX) structure, and the lithium oxide is configured to phase-transform from the DRX structure into a spinel-like structure during charging so as to alleviate and/or prevent rate capability decrease and irreversible voltage drop caused by lithium and manganese existing in excess in the lithium oxide, and a lithium secondary battery embodiment including the same.

First claim

What is claimed is:

1 . A cathode active material comprising:
a lithium oxide configured to enable intercalation and deintercalation of lithium; wherein the lithium oxide is represented by Li 1.05-x Mn 0.95-y M y O 2-z F z ; wherein M is at least one selected from the group consisting of Ti, Al, Nb, Mo, V, Cr, and Mg; wherein 0≤x≤0.5, 0≤y≤0.45, and 0<z≤0.6; and wherein the lithium oxide is configured such that:
at least a part of the lithium oxide is phase-transformed from a disordered rocksalt structure into a spinel-like structure during charging;
at least a part of the lithium oxide is phase-transformed from the spinel-like structure to the disordered rocksalt structure during discharging;
the disordered rocksalt structure and the spinel-like structure are mixed in a charged state; and
at least the disordered rocksalt structure exists in a discharged state.

2 . The material of claim 1 , wherein, as an amount of Mn in the lithium oxide increases, a degree of phase transformation during charging is increased.

3 . The material of claim 1 , wherein, a diffraction peak corresponding to a (111) plane derived from the spinel-like structure is observed in results of XRD analysis of the lithium oxide during charging.

4 . The material of claim 3 , wherein the diffraction peak occurs at a diffraction angle 2θ of 18° to 19°.

5 . The material of claim 1 , wherein y is 0.19 or less.

6 . The material of claim 5 , wherein the lithium oxide is configured such that, during charging and discharging of a lithium secondary battery using the cathode active material in a cathode performed under charge/discharge conditions of, in one cycle, a cut-off voltage of 1.5 V to 4.8 V, and with a constant current of 40 mA/g, voltage loss in a 30th cycle is 5.9% or less.

7 . The material of claim 5 , wherein, during initially charging of a lithium secondary battery using the cathode active material in a cathode at a voltage of 4.6 V, a phase transformation rate, calculated through a two-phase model based on Rietveld refinement of X-ray diffraction patterns, is 3.4% to 18%.

8 . The material of claim 5 , wherein a phase transformation rate from the disordered rocksalt structure into the spinel-like structure during charging is equal to or greater than a phase transformation rate from the spinel-like structure into the disordered rocksalt structure during discharging.

9 . The material of claim 5 , wherein the lithium oxide is Li 1.05 Mn 0.76 Ti 0.19 O 1.8 F 0.2 .

10 . The material of claim 1 , wherein y is 0.05 or less.

11 . The material of claim 10 , wherein the lithium oxide is configured such that, during charging and discharging of a lithium secondary battery using the cathode active material in a cathode performed under charge/discharge conditions of, in one cycle, a cut-off voltage of 1.5 V to 4.8 V, and with a constant current of 40 mA/g, voltage loss in a 30th cycle is 1.8% or less.

12 . The material of claim 10 , wherein, during initially charging of a lithium secondary battery using the cathode active material in a cathode at a voltage of 4.6 V, a phase transformation rate, calculated through a two-phase model based on Rietveld refinement of X-ray diffraction patterns, is 14% to 18%.

13 . The material of claim 10 , wherein a phase transformation rate from the disordered rocksalt structure into the spinel-like structure during charging exceeds a phase transformation rate from the spinel-like structure into the disordered rocksalt structure during discharging.

14 . The material of claim 10 , wherein the lithium oxide is configured such that, during charging and discharging of a lithium secondary battery using the cathode active material in a cathode performed under charge/discharge conditions of, in one cycle, a cut-off voltage of 1.5 V to 4.8 V, and with a constant current of 40 mA/g, the lithium secondary battery has flat potential characteristics at 3 V and 4 V in a graph configured such that an X-axis represents specific capacity and a Y-axis represents voltage (V).

15 . The material of claim 10 , wherein the lithium oxide is Li 1.05 Mn 0.90 Ti 0.05 O 1.8 F 0.2 .

16 . A cathode comprising a cathode active material, wherein the cathode active material comprises a lithium oxide configured to enable intercalation and deintercalation of lithium,
wherein the lithium oxide is represented by Li 1.05-x Mn 0.95-y M y O 2-z F z ,
wherein M is at least one selected from the group consisting of Ti, Al, Nb, Mo, V, Cr, and Mg, and
wherein 0≤x≤0.5, 0≤y≤0.45, and 0<z≤0.6, and
wherein the lithium oxide is configured such that:
at least a part of the lithium oxide is phase-transformed from a disordered rocksalt structure into a spinel-like structure during charging,
at least a part of the lithium oxide is phase-transformed from the spinel-like structure to the disordered rocksalt structure during discharging,
the disordered rocksalt structure and the spinel-like structure are mixed in a charged state, and
at least the disordered rocksalt structure exists in a discharged state.

17 . A lithium secondary battery comprising:
an anode; a cathode comprising a cathode active material; and an electrolyte interposed between the cathode and the anode; wherein the cathode active material comprises a lithium oxide configured to enable intercalation and deintercalation of lithium, wherein the lithium oxide is represented by Li 1.05-x Mn 0.95-y M y O 2 -2F z , wherein M is at least one selected from the group consisting of Ti, Al, Nb, Mo, V, Cr, and Mg, and wherein 0≤x≤0.5, 0≤y≤0.45, and 0<z≤0.6, and wherein the lithium oxide is configured such that:
at least a part of the lithium oxide is phase-transformed from a disordered rocksalt structure into a spinel-like structure during charging,
at least a part of the lithium oxide is phase-transformed from the spinel-like structure to the disordered rocksalt structure during discharging,
the disordered rocksalt structure and the spinel-like structure are mixed in a charged state, and
at least the disordered rocksalt structure exists in a discharged state.

18 . The battery of claim 17 , wherein y is 0.19 or less.

19 . The battery of claim 18 , wherein the lithium oxide is Li 1.05 Mn 0.76 Ti 0.19 O 1.8 F 0.2 .

20 . The battery of claim 17 , wherein y is 0.05 or less.

Assignees

• Hyundai Motor Co Ltd
• Kia Corp
• Ulsan Nat Inst Science & Tech Unist

Inventors

• Park Je Sik
• Min Hong-Seok
• Noh Sung Woo
• Seo Jeong Hyun
• Lim Chung Bum
• Seong Ju Yeong
• Seo Im Sul
• Seo Dong Hwa
• Lee Eun Ryeol
• Park Sang Wook

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/0447

  of complete cells or cells stacks · CPC title