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KR-20260063396-A - POSITIVE ELECTRODE AND RECHARGEABLE LITHIUM BATTERY INCLUDING THE SAME

KR20260063396AKR 20260063396 AKR20260063396 AKR 20260063396AKR-20260063396-A

Abstract

The present invention relates to a lithium secondary battery comprising: a positive electrode including a current collector; an electrolyte; and a negative electrode, wherein the positive electrode comprises a first positive active material layer on the current collector and a second positive active material layer on the first positive active material layer, and the second positive active material layer comprises: a positive active material comprising a lithium composite transition metal oxide; a plurality of pores; and a residual layer between the positive active material and the pores, and the residual layer comprises sulfur (S).

Inventors

  • 서성진

Assignees

  • 삼성에스디아이 주식회사

Dates

Publication Date
20260507
Application Date
20241030

Claims (20)

  1. A positive electrode including the entire current collector; Electrolyte; and Includes a cathode, The above positive electrode comprises a first positive active material layer on the current collector and a second positive active material layer on the first positive active material layer, and The above second positive active material layer is: Anode active material comprising a lithium complex transition metal oxide; Multiple pores; and It includes a residual layer between the positive electrode active material and the pores, A lithium secondary battery in which the above residual layer contains sulfur (S).
  2. In Article 1, A lithium secondary battery in which the porosity of the second positive active material layer is greater than the porosity of the first positive active material layer.
  3. In Article 1, The above electrolyte includes additives, but, A lithium secondary battery comprising a bicyclic sulfate-based compound, the above additive.
  4. In Paragraph 3, The above bicyclic sulfate compound is a lithium secondary battery represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, A1 , A2 , A3 , and A4 are independently covalent, substituted or unsubstituted alkylene, carbonyl, or sulfinyl groups having 1 to 5 carbon atoms, provided that A1 and A2 are not simultaneously covalent, and A3 and A4 are not simultaneously covalent.
  5. In Paragraph 4, A lithium secondary battery comprising at least one of the compounds represented by the above chemical formula 1 to the compounds represented by the following chemical formulas 1-1 to 1-7: [Chemical Formula 1-1] [Chemical Formula 1-2] [Chemical Formula 1-3] [Chemical Formula 1-4] [Chemical Formula 1-5] [Chemical Formula 1-6] [Chemical Formula 1-7] .
  6. In Paragraph 3, The above residual layer is a lithium secondary battery derived from the above additive.
  7. In Paragraph 3, A lithium secondary battery in which the pores of the second positive active material layer are formed by an additive in the second positive active material layer being dissolved into the electrolyte.
  8. In Paragraph 3, A lithium secondary battery in which the first positive active material layer does not include the residual layer.
  9. In Article 1, The above positive active material comprises lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), lithium iron phosphate oxide (LFP), or a combination thereof, in a lithium secondary battery.
  10. In Article 1, A lithium secondary battery in which the above positive electrode further comprises a binder or a conductive material.
  11. In Article 1, The above electrolyte is a lithium secondary battery further comprising an organic solvent and a lithium salt.
  12. In Article 1, A lithium secondary battery in which the porosity of the above positive electrode decreases at the interface between the first positive electrode active material layer and the second positive electrode active material layer.
  13. Preparing a first positive active material layer by applying a first positive slurry onto a current collector; Preparing a second positive active material layer by applying a second positive slurry onto the first positive active material layer; and The method includes providing an electrolyte on the first and second positive active material layers, wherein The above second anode slurry includes an additive, and Providing the above electrolyte is: Eluting the additive from the second positive active material layer; and A method for manufacturing a lithium secondary battery, comprising forming a plurality of pores within the second positive active material layer by the eluted additive.
  14. In Article 13, A method for manufacturing a lithium secondary battery, wherein the ratio of the concentration of the additive in the second anode slurry to the concentration of the additive in the first anode slurry is 100 to 1000.
  15. In Article 13, The second positive active material layer further comprises a positive active material and a residual layer between the positive active material and the pores, and A method for manufacturing a lithium secondary battery, wherein the above residual layer contains sulfur (S).
  16. In Article 13, A method for manufacturing a lithium secondary battery in which the porosity of the second positive active material layer is greater than the porosity of the first positive active material layer.
  17. In Article 13, A method for manufacturing a lithium secondary battery, wherein the porosity of the positive electrode of the lithium secondary battery is reduced at the interface between the first and second positive electrode active material layers.
  18. In Article 13, A method for manufacturing a lithium secondary battery, wherein the above additive is represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, A1 , A2 , A3 , and A4 are independently covalent, substituted or unsubstituted alkylene, carbonyl, or sulfinyl groups having 1 to 5 carbon atoms, provided that A1 and A2 are not simultaneously covalent, and A3 and A4 are not simultaneously covalent.
  19. The whole house; A first positive active material layer on the above current collector; and It includes a second positive active material layer on the first positive active material layer, The above second positive active material layer is: Anode active material comprising a lithium complex transition metal oxide; Multiple pores; and It includes a residual layer between the positive active material and the pores, The above residual layer is a positive electrode for a lithium secondary battery containing sulfur (S).
  20. In Article 19, A positive electrode for a lithium secondary battery, wherein the porosity of the second positive electrode active material layer is greater than the porosity of the first positive electrode active material layer.

Description

Positive electrode for lithium secondary battery and lithium secondary battery including the same This invention relates to a positive electrode for a lithium secondary battery and a lithium secondary battery containing the same. Recently, accompanied by the rapid proliferation of battery-powered electronic devices such as mobile phones, laptop computers, and electric vehicles, the demand for high-energy-density, high-capacity rechargeable batteries is rapidly increasing. Accordingly, research and development to improve the performance of lithium-ion batteries is actively underway. A lithium secondary battery is a battery comprising a positive electrode and a negative electrode containing an active material capable of lithium ion intercalation and deintercalation, and an electrolyte, which produces electrical energy through oxidation and reduction reactions when lithium ions are intercalated or deintercalated from the positive and negative electrodes. FIG. 1 is a conceptual diagram briefly illustrating a lithium secondary battery according to embodiments of the present invention. FIGS. 2 to 5 are cross-sectional views schematically illustrating a lithium secondary battery according to one embodiment. FIG. 6 is a cross-sectional view of a lithium secondary battery according to one embodiment of the present invention. FIG. 7 is a cross-sectional view of a positive electrode of a lithium secondary battery according to one embodiment of the present invention. FIG. 8 is an enlarged view of the M region according to one embodiment of the present invention. FIG. 9 is an enlarged view of the M region according to a comparative example of the present invention. Figure 10 is a graph showing the porosity according to the X direction of Figure 7. FIG. 11 is a graph showing the temperature and voltage according to the charging of each of the embodiments and comparative examples of the present invention. In order to fully understand the structure and effects of the present invention, preferred embodiments of the present invention are described with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and various modifications can be made. The description of these embodiments is provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention. In this specification, when a component is described as being on another component, it means that it may be formed directly on the other component or that a third component may be interposed between them. Additionally, in the drawings, the thicknesses of the components are exaggerated for the effective description of the technical content. Throughout the specification, parts indicated by the same reference numeral represent the same components. Unless otherwise specified in this specification, the singular form may also include the plural. Additionally, unless otherwise specified, "A or B" may mean "comprising A, comprising B, or comprising A and B." As used herein, "comprises" and/or "comprising" do not exclude the presence or addition of one or more other components to the mentioned components. In this specification, "combination of these" may mean a mixture of components, a laminate, a composite, a copolymer, an alloy, a blend, and a reaction product, etc. Unless otherwise defined in this specification, the particle size may be the average particle size. Additionally, the particle size refers to the average particle size (D50), which means the diameter of the particle whose cumulative volume in the particle size distribution is 50% by volume. The average particle size (D50) may be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) image or a scanning electron microscope (SEM) image. Alternatively, the average particle size (D50) value may be obtained by measuring using a measuring device utilizing dynamic light scattering, performing data analysis to count the number of particles for each particle size range, and then calculating from this. Alternatively, it may be measured using a laser diffraction method. When measuring by laser diffraction, more specifically, after dispersing the particles to be measured in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasound of about 28 kHz at an output of 60 W, and then the average particle size (D50) at 50% of the particle size distribution in the measuring device can be calculated. FIG. 1 is a conceptual diagram briefly illustrating a lithium secondary battery according to embodiments of the present invention. Referring to FIG. 1, the lithium secondary battery may include a positive electrode (10