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KR-20260064516-A - SEPARATOR FOR ELECTROCHEMICAL DEVICE AND ELECTROCHEMICAL DEVICE INCLUDING THE SAME

KR20260064516AKR 20260064516 AKR20260064516 AKR 20260064516AKR-20260064516-A

Abstract

The separator for an electrochemical device according to the present invention comprises a porous substrate and a coating layer formed on at least one surface of the porous substrate, wherein the coating layer comprises a polymer binder, inorganic particles, and hexagonal boron nitride, and the inorganic particles have a dielectric constant of 150 or higher.

Inventors

  • 김민지
  • 김지현
  • 황선우
  • 가경륜
  • 김민규

Assignees

  • 주식회사 엘지에너지솔루션

Dates

Publication Date
20260507
Application Date
20251001
Priority Date
20241030

Claims (10)

  1. porous substrate; and It includes a coating layer formed on at least one surface of the above-mentioned porous substrate, and The above coating layer comprises a polymer binder, inorganic particles, and hexagonal boron nitride, and The above inorganic particles are separators for electrochemical devices having a dielectric constant of 150 or higher.
  2. In paragraph 1, The above inorganic particles are BaTiO3 , Pb(Zr,Ti) O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT, 0<x<1, 0<y<1), Pb(Mg 1/3 Nb 2/3 ) O3 - PbTiO3 (PMN-PT), HfO2 , SrTiO3 , SnO2 , CeO2 , NiO, ZnO, ZrO2 , Y2O3 , TiO2 , or a mixture thereof, forming a separator for an electrochemical device.
  3. In paragraph 1, The above inorganic particles are separators for electrochemical devices, having an average particle size (D50) of 200 nm or more and 1,000 nm or less.
  4. In paragraph 1, A separator for an electrochemical device, wherein the volume ratio of the inorganic particles and the hexagonal boron nitride is 7:1 to 30:1.
  5. In paragraph 1, A separator for an electrochemical device, wherein the average diameter of the hexagonal boron nitride is 100 nm or more and 300 nm or less.
  6. In paragraph 1, A separator for an electrochemical device, wherein the aspect ratio of the hexagonal boron nitride is 5 or more and 30 or less.
  7. In paragraph 1, The above coating layer is a separator for an electrochemical device comprising 10 volume% or less of the hexagonal boron nitride.
  8. In paragraph 1, The above coating layer comprises 10 volume% or more and 30 volume% or less of the polymer binder, for a separator for an electrochemical device.
  9. In paragraph 1, A separator for an electrochemical device, wherein the thickness of the coating layer is 0.5 μm or more and 2 μm or less.
  10. An electrochemical device comprising an anode, a cathode, and a separator disposed between the anode and the cathode, The above separator is an electrochemical device, which is a separator for an electrochemical device according to claim 1.

Description

Separator for electrochemical device and electrochemical device including the same This application claims the benefit of priority based on Korean Patent Application No. 10-2024-0150287 dated October 30, 2024, and all contents disclosed in the document of said Korean patent application are incorporated herein as part of this specification. The present invention relates to a separator for an electrochemical device and an electrochemical device including the same. Electrochemical devices convert chemical energy into electrical energy using electrochemical reactions; recently, lithium-ion batteries, which offer high energy density and voltage, long cycle life, and applicability to various fields, are widely used. A lithium secondary battery may include an electrode assembly manufactured with a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes, and the electrode assembly may be manufactured by housing it in a case together with an electrolyte. Meanwhile, the separator of a lithium secondary battery prevents electrical contact between the positive and negative electrodes while enabling the movement of lithium ions between the electrodes, playing a crucial role in the safety and performance of the battery. Hereinafter, each component of the present invention is described in more detail so that a person skilled in the art to which the present invention pertains can easily implement it; however, this is merely an example, and the scope of the rights of the present invention is not limited by the following. The term “comprising” as used herein is used when listing materials, compositions, devices, and methods useful to the present invention, and is not limited to the examples listed. As used herein, “about” and “substantially” are used to mean a range of numerical or degree or an approximation thereof, taking into account inherent manufacturing and material tolerances (±5%), and are used to prevent an infringer from unfairly exploiting the disclosure in which precise or absolute figures provided to aid in understanding the invention are mentioned. As used in this specification, the term “electrochemical device” may refer to primary batteries, secondary batteries, supercapacitors, etc. The separator may include a coating layer comprising a polymer binder and inorganic particles on at least one surface of a porous substrate. The inorganic particles may be connected to other inorganic particles by the polymer binder to form an interstitial volume, and lithium ions may move through said interstitial volume. In addition to fixing the inorganic particles, the polymer binder may impart adhesion to the coating layer, and the coating layer may adhere to the porous substrate and the electrode, respectively. Large amounts of gas that may be generated during the storage or operation of electrochemical devices increase the resistance of the devices and cause problems such as reduced output and cycle characteristics. Accordingly, there have been attempts to apply inorganic particles with high dielectric constants to the coating layer to reduce gas generation. Inorganic particles with high dielectric constants have the advantage of low moisture adsorption and inhibit the decomposition of salts within the electrolyte upon impregnation, thereby reducing gas generation caused by side reactions of salts. However, inorganic particles with high dielectric constants have a problem of reduced dispersibility due to their high density, which causes a rapid sedimentation rate within the slurry. Consequently, if a non-uniform coating layer is formed, the physical properties of the separator membrane deteriorate. Considering these points, the present invention provides a method for forming a uniform coating layer by lowering the sedimentation rate of inorganic particles in a coating slurry, and a separation membrane and an electrochemical device utilizing the same. Although the present invention has been described below by way of examples, the present invention is not limited thereto and may include a combination of one or more configurations of specific examples and examples by those skilled in the art to which the present invention belongs, and various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below. A separator for an electrochemical device according to one embodiment of the present invention comprises a porous substrate and a coating layer formed on at least one surface of the porous substrate, wherein the coating layer comprises a polymer binder, inorganic particles, and hexagonal boron nitride (e.g., h-BN), and the inorganic particles have a dielectric constant of 150 or higher. The porous substrate may be a porous membrane having a plurality of pores formed therein, which electrically insulates the positive electrode and the negative electrode to prevent a short