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EP-4738450-A1 - ELECTRODE FOR LITHIUM SECONDARY BATTERY AND LITHIUM SECONDARY BATTERY

EP4738450A1EP 4738450 A1EP4738450 A1EP 4738450A1EP-4738450-A1

Abstract

An electrode for a lithium secondary battery that includes: a metal current collector; and an active material layer that is formed on the metal current collector and comprises an electrode active material, a conductive material, and an oxide-based solid electrolyte having a lithium ion source, wherein the electrode active material and the oxide-based solid electrolyte are dispersed in the active material layer in the form of particles and have a particle size distribution of span: 1 or less. A lithium secondary battery includes the electrode as a positive electrode. A method for manufacturing the electrode for a lithium secondary battery includes: mixing and dispersing the oxide-based solid electrolyte and a solvent to prepare a solid electrolyte dispersion; mixing the solid electrolyte dispersion, the electrode active material, and the conductive material to prepare an electrode active material slurry; and applying the electrode active material slurry to an electrode current collector.

Inventors

  • LEE, Sangryeo
  • BYUN, SEOUNGWOO
  • JANG, Eunji
  • RYU, JIHOON
  • LIM, Taeseob
  • KIM, DONG KYU
  • LEE, HYUNJUN

Assignees

  • LG Energy Solution, Ltd.

Dates

Publication Date
20260506
Application Date
20240828

Claims (15)

  1. An electrode for a lithium secondary battery comprising: a metal current collector; and an active material layer that is formed on the metal current collector and comprises an electrode active material, a conductive material, and an oxide-based solid electrolyte having a lithium ion source, wherein the electrode active material and the oxide-based solid electrolyte are particles dispersed in the active material layer and have a particle size distribution of span: 1 or less.
  2. The electrode for a lithium secondary battery of claim 1, wherein: the electrode active material comprises a lithium metal oxide including lithium, and two or more of nickel, manganese, cobalt or aluminum, and the lithium metal oxide includes60 mol.% or more of nickel based on a total metal content excluding lithium.
  3. The electrode for a lithium secondary battery of claim 1, wherein: the oxide-based solid electrolyte includes at least one lithium metal oxide or lithium metal phosphate selected from a Nasicon-type solid electrolyte, a Lisicon-type solid electrolyte, a Garnet-type solid electrolyte, a Perovskite-type solid electrolyte, or a LiPON-type solid electrolyte.
  4. The electrode for a lithium secondary battery of claim 1, wherein: the oxide-based solid electrolyte includes at least one of a LAGP(lithium aluminum germanium phosphate)-based compound, a LLZO(lithium lanthanum zirconium oxide)-based compound, a LATP(lithium aluminum titanium phosphate)-based compound, a LLZTO(lithium lanthanum zirconium tantalum oxide)-based compound, a LLTO(lithium lanthanum titanium oxide)-based compound, a LSTP(lithium silicon titanium phosphate)-based compound, or a LGPO(lithium germanium phosphate)-based compound.
  5. The electrode for a lithium secondary battery of claim 1, wherein: the oxide-based solid electrolyte has one or more particle size distributions of D50: 100 nm to 1 µm or D90: 400 nm to 1.5 µm.
  6. The electrode for a lithium secondary battery of claim 1, wherein: the oxide-based solid electrolyte has a particle size distribution of D50: 300 nm to 700 nm and D90: 400nm to 900 nm.
  7. The electrode for a lithium secondary battery of claim 1, wherein: the oxide-based solid electrolyte has a sample variance of 0.04 or less, as expressed by a following Mathematical Equation 1 through EDS analysis: s 2 = ∑ y − y ¯ 2 n − 1 = SS df wherein: S 2 is sample variance, y is a variable, y is sample mean, n is sample size, SS is a sum of squared deviations, and df is a degree of freedom.
  8. The electrode for a lithium secondary battery of claim 1, wherein: the oxide-based solid electrolyte is included in an amount of from 0.3 to 5 parts by weight based on 100 parts by weight of the electrode active material.
  9. The electrode for a lithium secondary battery of claim 1, wherein: the conductive material includes carbon nanotubes or carbon nanofibers, and the active material layer further includes a binder.
  10. A lithium secondary battery comprising: a positive electrode; a negative electrode; and an electrolyte including a lithium salt and a non-aqueous organic solvent, wherein the electrode for a lithium secondary battery according to claim 1 is included as a positive electrode.
  11. The lithium secondary battery according to claim 10, wherein: the lithium salt includes at least one of: LiCl, LiBr, LiI, LiBF 4 , LiClO 4 , LiB 10 Cl 10 , LiAlCl 4 , LiAlO 2 , LiPF 6 , LiCF 3 SO 3 , LiCH 3 CO 2 , LiCF 3 CO 2 , LiAsF 6 , LiSbF 6 , LiCH 3 SO 3 , LiFSI (lithium bis(fluorosulfonyl) imide, LiN(SO 2 F) 2 ), LiBETI (lithium bis(perfluoroethanesulfonyl) imide, LiN(SO 2 CF 2 CF 3 ) 2 or LiTFSI (lithium bis(trifluoromethanesulfonyl) imide, LiN(SO 2 CF 3 ) 2 ).
  12. The lithium secondary battery according to claim 10, wherein: the lithium salt is contained in the electrolyte at a concentration of from 0.5M to 6M.
  13. The lithium secondary battery of claim 10, wherein: the lithium secondary battery further includes a separation membrane interposed between the positive electrode and the negative electrode, or the electrolyte has a form of an electrolyte membrane or an electrolyte film including the lithium salt and a non-aqueous organic solvent in a polymer matrix, which is interposed between the positive electrode and the negative electrode.
  14. A method for manufacturing an electrode for a lithium secondary battery according toclaim 1, the method comprising: mixing and dispersing the oxide-based solid electrolyte and a solvent to prepare a solid electrolyte dispersion; mixing the solid electrolyte dispersion, the electrode active material, and the conductive material to prepare an electrode active material slurry; and applying the electrode active material slurry to the metal current collector.
  15. The method for manufacturing an electrode for a lithium secondary battery according to claim 14, wherein: mixing and dispersing the oxide-based solid electrolyte and a solvent to prepare the solid electrolyte dispersion is performed using a bead-milling method.

Description

[TECHNICAL FIELD] Cross Citation with Related Application(s) This application is a national phase entry of International Application No. PCT/KR2024/012861 filed on August 28, 2024, which claims priority from and the benefit of Korean Patent Application No. 10-2023-0113515 filed on August 29, 2023, all of which are incorporated herein by reference in their entirety. TECHNICAL FIELD The present disclosure relates to an electrode for a lithium secondary battery that can improve output characteristics and low-temperature characteristics, etc. of a lithium secondary battery, and a lithium secondary battery comprising the same. [BACKGROUND] Recently, demand for high-capacity, high-output, long-life and high-stability lithium secondary batteries has been increased as an application area of lithium secondary batteries has rapidly expanded to power storage supply of large-area devices, such as automobiles and power storage devices, as well as electricity, electronics, communication, and power supply of electronic devices such as computers. A lithium secondary battery is generally configured to include a positive electrode, a negative electrode, a separation membrane, a lithium salt, and an electrolyte containing an organic solvent, wherein movement of lithium ions occurs through the electrolyte in a charge and discharge process. Lithium ions in the electrolyte exist in a solvated state surrounded by an organic solvent. Therefore, in order for the lithium ions in this electrolyte to move and be inserted into the electrode active material, lithium ions undergo a desolvation process in which lithium ions are separated or desorbed from the organic solvent molecules. Therefore, smooth progress of this desolvation process may affect the output, resistance, stability or the like of a lithium secondary battery. On the other hand, in recent years, as higher capacity and higher output of the lithium secondary batteries are required, new electrolytes is being actively developed. In particular, in order to accelerate the desolvation of lithium ions and increase the output or the like of a lithium secondary battery, new electrolyte compositions or the like are being proposed, such as containing a lithium salt at a high concentration, or changing the composition of the organic solvent to form a locally high concentration area of a lithium salt around the electrode. However, when applying the new electrolyte composition containing a high concentration of lithium salts, it may cause the problem of a decrease in fluidity due to an increase in the viscosity of the electrolyte. In particular, there is a disadvantage in that the ionic conductivity of the electrolyte decreases at low temperatures, which leads to a deterioration of the low-temperature characteristics of a lithium secondary battery, such as an increase in resistance or a decrease in battery output. Therefore, there is a continuing need to develop a technology that can accelerate the desolvation of lithium ions in the electrolyte, thereby improving the output characteristics of a lithium secondary battery as well as maintaining excellent low-temperature characteristics. [DETAILED DESCRIPTION OF THE INVENTION] [Technical Problem] Thus, it is an object of the present disclosure to provide an electrode for a lithium secondary battery that can accelerate the desolvation of lithium ions in the electrolyte, thereby improving the output characteristics of a lithium secondary battery as well as maintaining excellent low-temperature characteristics such as high output at low temperatures. It is another object of the present disclosure to provide a lithium secondary battery comprising the same, which exhibit improved output characteristics and low-temperature characteristics. [Technical Solution] Hereinafter, an electrode for a lithium secondary battery, and the like according to specific aspects of the present disclosure will be described. Terms or words used in the specification and the appended claims should not be construed as limited to ordinary or dictionary meanings, and the present disclosure should be construed with meanings and concepts that are consistent with the technical idea of the present disclosure based on the principle that the inventors may appropriately define concepts of the terms to appropriately describe their own invention in the best way. The terms used herein are provided to describe exemplary aspects but not to limit the inventive concept. The singular forms include plural forms unless the context clearly indicates otherwise. It should be understood that the terms "comprise," "include", "have", etc. are used herein to specify the presence of stated features, integers, steps, components or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof. Electrode for lithium secondary battery According to an aspect of the present disclosure, there is provided an electrod