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KR-20260066679-A - POSITIVE ELECTRODE ACTIVE MATERIAL AND POSITIVE ELECTRODE OF THE SAME

KR20260066679AKR 20260066679 AKR20260066679 AKR 20260066679AKR-20260066679-A

Abstract

The present invention relates to a positive electrode active material capable of realizing a battery with improved initial resistance characteristics and lifespan characteristics, and a positive electrode containing the same. The positive electrode is a positive electrode active material in the form of a single particle, and the positive electrode contains a positive electrode active material layer comprising 80% by weight or more of the positive electrode active material relative to the total weight of the positive electrode active material layer. After rolling, the density of the positive electrode active material layer is 2.7 g/cm³ or more, and when the positive electrode active material layer is analyzed by XRD, the ratio of the area of the (003) peak to the area of all peaks identified in the 2θ 10˚~90˚ range satisfies 30% or more.

Inventors

  • 정원식
  • 김종필
  • 이응주
  • 이태영
  • 최환영

Assignees

  • 주식회사 엘지화학

Dates

Publication Date
20260512
Application Date
20260409
Priority Date
20220520

Claims (18)

  1. As a positive active material in the form of a single particle, A positive electrode comprising a positive electrode active material layer comprising at least 80% by weight of the above positive electrode active material relative to the total weight of the positive electrode active material layer, and after rolling such that the density of the positive electrode active material layer is at least 2.7 g/ cm³ , when the positive electrode active material layer is analyzed by XRD, the ratio of the area of the (003) peak to the area of all peaks identified in the 2θ 10˚~90˚ range satisfies at least 30%.
  2. In claim 1, A positive electrode active material that satisfies a difference in the ratio of the area of the (003) peak to the area of all peaks identified in the 2θ 10˚~90˚ range when the positive electrode active material layer before and after rolling is analyzed by XRD, such that the difference is 10% or more.
  3. In claim 1, The above single-particle positive active material is a positive active material in which the ratio of the length in the a-axis direction to the length in the c-axis direction of the crystal is greater than 1.
  4. In claim 1, The above-mentioned single-particle type positive active material is a positive active material composed of 1 to 50 single-crystal particles.
  5. In claim 4, The above single crystal particles are a positive active material having an average particle size (D EBSD ) of 0.1㎛ to 10㎛.
  6. In claim 1, The above-mentioned single-particle positive active material is a positive active material that is a lithium composite transition metal oxide containing nickel (Ni), cobalt (Co), and manganese (Mn).
  7. In claim 6, The above lithium composite transition metal oxide is a positive electrode active material containing 60 mol% or more of nickel (Ni) among the total metals excluding lithium.
  8. In claim 6, The above lithium complex transition metal oxide is a positive electrode active material having a composition represented by the following chemical formula 1: [Chemical Formula 1] Li a Ni b Co c Mn d M 1 e O 2 In the above chemical formula 1, M 1 is one or more selected from Al, Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, Sn, Y, Zn, F, P, and S, and 0.90≤a≤1.1, 0.60≤b<1.0, 0<c<0.40, 0<d<0.40, 0≤e≤0.10, b+c+d+e=1.
  9. The whole house; and A positive electrode comprising a positive electrode active material layer located on the above current collector, The above positive active material layer is a positive electrode comprising a positive active material according to claim 1.
  10. In claim 9, An anode in which, when the anode active material layer before and after rolling is analyzed by XRD, the difference in the ratio of the area of the (003) peak to the area of all peaks identified in the 2θ 10˚~90˚ range is 10% or more.
  11. In claim 9, A positive electrode having a (cosθ) ² value of 0.6 or greater, where θ is the angle formed by the lithium migration path of the above-mentioned single-particle positive electrode active material and the axis parallel to the upper surface of the above-mentioned current collector.
  12. In claim 9, The above-mentioned single-particle positive active material is a positive electrode in which the c-axis direction of the crystal is aligned perpendicular to the upper plane of the current collector.
  13. In claim 9, The above single-particle type positive active material is a positive electrode in which the ratio of the length in the a-axis direction to the length in the c-axis direction of the crystal is greater than 1.
  14. In claim 9, The above-mentioned single-particle type positive electrode active material is a positive electrode composed of 1 to 50 single-crystal particles.
  15. In claim 14, The above single crystal particles are anodes having an average particle size (D EBSD ) of 0.1 μm to 10 μm.
  16. In claim 9, The above-mentioned single-particle cathode active material is a cathode that is a lithium composite transition metal oxide containing nickel (Ni), cobalt (Co), and manganese (Mn).
  17. In claim 16, The above lithium composite transition metal oxide is an anode containing 60 mol% or more of nickel (Ni) among the total metals excluding lithium.
  18. In claim 16, The above lithium complex transition metal oxide is an anode having a composition represented by the following chemical formula 1: [Chemical Formula 1] Li a Ni b Co c Mn d M 1 e O 2 In the above chemical formula 1, M 1 is one or more selected from Al, Zr, B, W, Mo, Cr, Nb, Mg, Hf, Ta, La, Ti, Sr, Ba, Ce, Sn, Y, Zn, F, P, and S, and 0.90≤a≤1.1, 0.60≤b<1.0, 0<c<0.40, 0<d<0.40, 0≤e≤0.10, b+c+d+e=1.

Description

Positive ELECTRODE ACTIVE MATERIAL AND POSITIVE ELECTRODE OF THE SAME The present invention relates to a positive electrode active material in the form of a single particle and a positive electrode containing the same. With the recent increase in technological development and demand for mobile devices and electric vehicles, the demand for secondary batteries as an energy source is rapidly increasing. A lithium secondary battery generally consists of a positive electrode, a negative electrode, a separator, and an electrolyte, and the positive and negative electrodes include an active material capable of lithium ion intercalation and deintercalation. Meanwhile, the cathode active material used in lithium secondary batteries generally has the form of spherical secondary particles formed by the aggregation of hundreds of submicron-sized fine primary particles. However, cathode active materials in the form of secondary particles have a problem in that the battery performance deteriorates as the secondary particles break down as the aggregated primary particles separate during repeated charging and discharging. To address these issues, active development of single-particle cathode active materials is underway; however, when manufacturing electrodes using these materials, there are difficulties in aligning the c-axis direction—the primary expansion direction of the single-particle cathode active material—as desired or quantifying the degree of alignment. Furthermore, if the c-axis direction, the primary expansion direction of the single-particle cathode active material, is not aligned and exists randomly, problems such as reduced battery lifespan, capacity degradation, and power output reduction occur. Consequently, there is a need for technology to overcome these challenges. Figure 1 is an SEM image of the positive electrode active material of Example 1. Figure 2 is an SEM image of the positive electrode active material of Comparative Example 1. Figure 3 is an SEM image of the positive electrode active material of Comparative Example 3. Figure 4 is XRD data of the anode active material layer before and after rolling of the anode containing the anode active materials of Examples 1 and 2 and Comparative Examples 3 and 4. Figure 5 is an EBSD Band Contrast (BC) image of a cross-section of an anode containing the anode active material of Example 1. Figure 6 is a diagram showing the angle between the c-axis direction vector (Euler angle) of the crystal grain and the direction vector perpendicular to the electrode (= angle between the lithium movement path (Li path) and the direction vector parallel to the electrode). Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. In this specification, the term "on" means not only cases where one configuration is formed on the immediate upper surface of another configuration, but also cases where a third configuration is interposed between these configurations. In this specification, "single-particle type positive active material" refers to a positive active material composed of 50 or fewer single-crystal particles, as opposed to a spherical secondary particle type positive active material formed by the aggregation of hundreds of primary particles manufactured by conventional methods. Specifically, in the present invention, the single-particle type positive active material may be a single single-crystal particle, or it may be in the form of aggregations of 2 to 50, 2 to 40, 2 to 30, 2 to 20, 2 to 15, 2 to 10, or 2 to 5 single-crystal particles. In this case, "single-crystal particle" refers to the smallest unit of a particle recognized when the positive active material is observed through a scanning electron microscope. In this specification, the average particle size (D 50 ) refers to the particle size at the 50% reference of the volume cumulative particle size distribution of the positive active material precursor, positive active material, or lithium transition metal oxide powder. The average particle size (D 50 ) can be measured using a laser diffraction method. For example, the particle size can be measured by dispersing the positive active material powder in a dispersion medium, introducing it into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), irradiating it