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EP-4207380-B1 - POSITIVE ELECTRODE ACTIVE MATERIAL, POSITIVE ELECTRODE ACTIVE MATERIAL SLURRY, POSITIVEELECTRODE, LITHIUM-ION SECONDARY BATTERY AND METHOD FOR PREPARING POSITIVE ELECTRODE ACTIVEMATERIAL

EP4207380B1EP 4207380 B1EP4207380 B1EP 4207380B1EP-4207380-B1

Inventors

  • CHIHARA, Kuniko
  • MATSUBARA, KEIKO

Dates

Publication Date
20260513
Application Date
20211224

Claims (15)

  1. A positive electrode active material for a lithium-ion secondary battery, comprising a lithium transition metal oxide, and an iodine-containing material at least partially covering the particles of the lithium transition metal oxide and containing iodine having an oxidation number of +3 to +7.
  2. The positive electrode active material for a lithium-ion secondary battery according to claim 1, wherein the iodine-containing material contains iodine having an oxidation number of +5 to +7.
  3. The positive electrode active material for a lithium-ion secondary battery according to claim 1 or 2, wherein the iodine-containing material contains iodine having an oxidation number of +7.
  4. The positive electrode active material for a lithium-ion secondary battery according to claim 1, wherein the iodine-containing material contains a periodate ion or a hydrogen periodate ion.
  5. The positive electrode active material for a lithium-ion secondary battery according to any one of claims 1 to 4, wherein the iodine-containing material contains a periodate ion IO 4 - .
  6. The positive electrode active material for a lithium-ion secondary battery according to claim 1, which shows a spectrum of I3d 5/2 having a peak at 622-626 eV, as determined by X-ray photoelectron spectroscopy.
  7. The positive electrode active material for a lithium-ion secondary battery according to claim 1, which comprises the iodine-containing material in an amount of 0.001-10.0 wt% based on the total weight of the positive electrode active material.
  8. A positive electrode active material slurry for a lithium-ion secondary battery comprising the positive electrode active material as defined in any one of claims 1 to 7.
  9. A positive electrode for a lithium-ion secondary battery, comprising a positive electrode active material layer, containing the positive electrode active material as defined in any one of claims 1 to 7 and formed on a current collector.
  10. A lithium-ion secondary battery comprising the positive electrode as defined in claim 9.
  11. A method for preparing the positive electrode active material for a lithium-ion secondary battery as defined in claim 1, the method comprising the steps of: mixing a lithium transition metal oxide with an iodine-containing starting material in a solid state to prepare an iodine-containing mixture; and firing the iodine-containing mixture, wherein the firing step comprises firing the iodine-containing mixture at a firing temperature of 150-500°C, and wherein the iodine-containing mixture is maintained at the firing temperature for a firing time of 1-12 hours, in the firing step.
  12. The method for preparing the positive electrode active material for a lithium-ion secondary battery according to claim 11, wherein the iodine-containing starting material comprises at least one selected from the group consisting of a simple substance of iodine, I 2 ; lithium iodide, LiI; sodium iodide, NaI; potassium iodide, KI; iodoform, CHI 3 ; carbon tetraiodide, CI 4 ; ammonium iodide, NH 4 I; iodic acid, HIO 3 ; lithium iodate, LiIO 3 ; sodium iodate, NaIO 3 ; potassium iodate, KIO 3 ; ammonium iodate, NH 4 IO 3 ; metaperiodic acid, HIO 4 ; orthoperiodic acid, H 5 IO 6 ; lithium periodate, LiIO 4 ; sodium periodate, NaIO 4 ; potassium periodate, KIO 4 ; iodine oxide (IV), I 2 O 4 ; iodine oxide (V), I 2 O 5 ; and iodine oxide (IV, V), I 4 O 9 .
  13. The method for preparing the positive electrode active material for a lithium-ion secondary battery according to claim 11 or 12, wherein the iodine-containing starting material comprises a simple substance of iodine, I 2 .
  14. The method for preparing the positive electrode active material for a lithium-ion secondary battery according to claim 11, wherein the iodine-containing starting material is mixed with the lithium transition metal oxide in an amount of 0.01-5 wt% based on the weight of the lithium transition metal oxide.
  15. The method for preparing the positive electrode active material for a lithium-ion secondary battery according to claim 11, wherein the firing step is carried out under ambient atmosphere.

Description

TECHNICAL FIELD The present disclosure relates to a positive electrode active material, a positive electrode active material slurry, a positive electrode, a lithium ion secondary battery and a method for preparing a positive electrode active material. BACKGROUND ART As technical development and needs for mobile instruments and electric vehicles have been increased, secondary batteries as energy sources have been increasingly in demand. Among such secondary batteries, lithium-ion secondary batteries having high energy density and voltage, long cycle life and low self-discharge rate have been commercialized and used widely. Recently, active studies have been conducted to provide such lithium-ion secondary batteries with high capacity. KR 2018 0071438 A describes a cathode active material comprising a core formed of a lithium containing metal oxide, and a coating layer which includes lithium iodide. However, in an attempt to provide a lithium-ion secondary battery with high capacity, there are cases where high-temperature life characteristics (also referred to as cycle characteristics) are not sufficiently realized. Therefore, there is a need for improving such characteristics. [References] [Patent Documents] Patent Document 1: Japanese Laid-Open Patent No. 2017-084673Patent Document 2: Japanese Laid-Open Patent No. 2009-016302Patent Document 3: Japanese Laid-Open Patent No. 2017-183101Patent Document 4: Japanese Laid-Open Patent No. 2018-516458Patent Document 5: Japanese Laid-Open Patent No. 2013-543219 DISCLOSURE Technical Problem The present disclosure is designed to solve the problems of the related art, and therefore the present disclosure is directed to providing a positive electrode active material for a lithium-ion secondary battery having excellent cycle characteristics at high temperature, a positive electrode active material slurry, a positive electrode, a lithium-ion secondary battery, and a method for preparing a positive electrode active material. Technical Solution According to the first embodiment of the present disclosure, there is provided a positive electrode active material for a lithium-ion secondary battery, including a lithium transition metal oxide, and an iodine-containing material at least partially covering the particles of the lithium transition metal oxide and containing iodine having an oxidation number of +3 to +7. As used herein, 'lithium transition metal oxide' means a compound containing lithium and a transition metal and having a transition metal-oxygen bonding, and also covers a compound containing a typical metal element, such as aluminum, or a non-metallic element, such as iodine, other than oxygen. In addition, 'iodine-containing material' means an material containing iodine. Further, the term 'covering' means 'at least partially covering the surface of an object', and also includes a chemical bonding to the surfaces of particles and physical covering of the surfaces of particles with no chemical bonding. For example, as determined by X-ray photoelectron spectroscopy (XPS) of the surfaces of active material particles, 'covering' may be determined by the detection of a peak derived from an iodine-containing material. According to the second embodiment of the present disclosure, there is provided the positive electrode active material for a lithium-ion secondary battery as defined in the first embodiment, wherein the iodine-containing material contains iodine having an oxidation number of +5 to +7. According to the third embodiment of the present disclosure, there is provided the positive electrode active material for a lithium-ion secondary battery as defined in the first or the second embodiment, wherein the iodine-containing material contains iodine having an oxidation number of +7. According to the fourth embodiment of the present disclosure, there is provided the positive electrode active material for a lithium-ion secondary battery as defined in any one of the first to the third embodiments, wherein the iodine-containing material contains a periodate ion or a hydrogen periodate ion. According to the fifth embodiment of the present disclosure, there is provided the positive electrode active material for a lithium-ion secondary battery as defined in any one of the first to the fourth embodiments, wherein the iodine-containing material contains a periodate ion (IO4-). According to the sixth embodiment of the present disclosure, there is provided the positive electrode active material for a lithium-ion secondary battery as defined in any one of the first to the fifth embodiments, which shows a spectrum of I3d5/2 having a peak at 622-626 eV, as determined by X-ray photoelectron spectroscopy. According to the seventh embodiment of the present disclosure, there is provided the positive electrode active material for a lithium-ion secondary battery as defined in any one of the first to the sixth embodiments, which includes the iodine-containing material in an amount of 0.001-1