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KR-20260063545-A - Positive electrode active material for lithium secondary battery and method for manufacturing the same, and the positive electrode and lithium secondary battery including the same

KR20260063545AKR 20260063545 AKR20260063545 AKR 20260063545AKR-20260063545-A

Abstract

The present invention relates to a positive electrode active material for a lithium secondary battery, and provides a positive electrode active material for a lithium secondary battery having excellent structural stability and improved electrochemical performance by controlling the moisture content and particle size of lithium composite transition metal precursor particles under constant temperature and humidity conditions, and a positive electrode and a secondary battery including the same.

Inventors

  • 장현석

Assignees

  • (주)포스코퓨처엠

Dates

Publication Date
20260507
Application Date
20241030

Claims (12)

  1. Lithium complex transition metal oxide particles represented by the following chemical formula 1; and It includes residual lithium present on the surface of the above lithium composite transition metal oxide particles, and The above residual lithium includes Li₂CO₃ , and the residual lithium drying ratio represented by the following formula (1) is 0.030 or higher, Cathode active material for lithium secondary batteries. [Chemical Formula 1] Li[Ni 1-xyz Co x Mn y Al z ]O 2 (x≤0.07, y≤0.10, z≤0.03) Equation ( 1 ): Residual Li₂CO₃ content of cathode active material / Moisture content of anhydrous LiOH (Here, the residual Li₂CO₃ content of the cathode active material refers to the content (weight%) of residual Li₂CO₃ contained in the cathode active material based on 100 weight% of the cathode active material, and the moisture content of the anhydrous LiOH refers to the content (weight%) of moisture contained in the anhydrous LiOH based on 100 weight% of the anhydrous LiOH added during the manufacturing process of the cathode active material.)
  2. In claim 1, The above positive active material contains moisture of 4 weight% or less, Cathode active material for lithium secondary batteries.
  3. In claim 1, The average particle size (D50) of the above lithium composite transition metal oxide particles is 10.0 μm or less, Cathode active material for lithium secondary batteries.
  4. In claim 1, The D90 of the above lithium composite transition metal oxide particles is 14.0 μm or less, Cathode active material for lithium secondary batteries.
  5. In claim 1, With an average energy density of 232.9 ± 0.3 mAh/g or higher under 0.1C charge conditions, Cathode active material for lithium secondary batteries.
  6. In claim 1, Having a BET specific surface area of 0.50 m² /g or more, Cathode active material for lithium secondary batteries.
  7. In preparing a lithium complex transition metal oxide represented by the following chemical formula 1, Step of preparing positive active material precursor particles; A step of adding anhydrous lithium hydroxide to the cathode active material precursor to contain moisture of 4 weight% or less based on the total weight of the cathode active material, and moistening it for 2 hours or less under constant temperature and humidity conditions; and A step comprising heat-treating the above moisture-containing positive electrode active material precursor, Method for manufacturing a positive electrode active material for a lithium secondary battery. [Chemical Formula 1] Li[Ni 1-xyz Co x Mn y Al z ]O 2 (x≤0.07, y≤0.10, z≤0.03)
  8. In claim 7, The above positive active material precursor is, A method for manufacturing a positive electrode active material for a lithium secondary battery represented by the following chemical formula 2. [Chemical Formula 2] Ni 1-xyz Co x Mn y Al z (OH) 2 (x≤0.07, y≤0.10, z≤0.03)
  9. In claim 7, After the above-mentioned moistening step, the method further comprises a step of washing and drying under conditions where the temperature of the solution having a pH of 9 to 12 is -10℃ to 15℃. Method for manufacturing a positive electrode active material for a lithium secondary battery.
  10. In claim 7, The above heat treatment step is performed in an oxygen or air atmosphere at 200°C to 600°C, Method for manufacturing a positive electrode active material for a lithium secondary battery.
  11. positive current collector; and It includes a positive active material layer formed on the positive current collector, and The above positive active material layer comprises a positive active material for a lithium secondary battery according to any one of claims 1 to 6, a positive electrode for a lithium secondary battery.
  12. A lithium secondary battery comprising: a positive electrode according to claim 11; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and an electrolyte.

Description

Positive electrode active material for lithium secondary battery and method for manufacturing the same, and the positive electrode and lithium secondary battery including the same The present invention relates to a positive electrode active material for a lithium secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same. More specifically, the invention relates to a positive electrode active material of NCM (nickel-cobalt-manganese ternary system) or NCMA (nickel-cobalt-manganese-aluminum quaternary system) containing high nickel, and a method for manufacturing the same. With the increasing technological development and demand for mobile devices, the demand for rechargeable batteries as an energy source is rapidly rising. Among these rechargeable batteries, lithium-ion batteries, which possess high energy density and voltage, long cycle life, and low self-discharge rates, have been commercialized and are widely used. In a lithium secondary battery, electrical energy is produced by oxidation and reduction reactions when lithium ions are inserted into or removed from the positive and negative electrodes, which are composed of active materials capable of lithium ion intercalation and deintercalation, with an organic or polymer electrolyte charged between them. Lithium cobalt oxide ( LiCoO2 ), lithium nickel oxide ( LiNiO2 ), lithium manganese oxide ( LiMnO2 or LiMn2O4 , etc. ), and lithium iron phosphate compounds ( LiFePO4 ) have been used as cathode active materials for lithium secondary batteries. In addition, as a method to improve the low thermal stability while maintaining the excellent reversible capacity of lithium nickel oxide ( LiNiO2 ), lithium composite metal oxides (hereinafter simply referred to as 'NCM-based lithium composite transition metal oxides' or 'NCA-based lithium composite transition metal oxides') in which a portion of nickel (Ni) is substituted with cobalt (Co) or manganese (Mn)/aluminum (Al) have been developed. However, the conventionally developed NCM-based/NCA-based lithium composite transition metal oxides had limitations in application due to insufficient capacity characteristics. To address these issues, research has recently been conducted to increase the nickel (Ni) content in NCM-based/NCA-based lithium oxides. However, in the case of high-nickel (High-Ni) NCM-based/NCA-based lithium oxides, there was a difficulty in strictly controlling sintering conditions, such as sintering temperature and sintering atmosphere, in order to form the material with an initial oxidation state of 3+ nickel (Ni) because nickel (Ni) tends to remain at an oxidation state of 2+. Furthermore, as the nickel (Ni) content increases, the crystals grow rapidly during sintering, making it difficult to control the crystal size. Additionally, there was a problem in that the structural and chemical stability of the cathode active material decreased, limiting the improvement of battery capacity and lifespan characteristics. Preferred embodiments of the present invention are described below. However, embodiments of the present invention may be modified in various other forms, and the technical concept of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the relevant technical field. The terms used in this application are used merely to describe specific examples. For this reason, singular expressions include plural expressions unless the context clearly requires them to be singular. Additionally, it should be noted that terms such as “comprising” or “comprising” used in this application are used to clearly indicate the presence of features, steps, functions, components, or combinations thereof described in the specification, and are not used to preliminarily exclude the existence of other features, steps, functions, components, or combinations thereof. Meanwhile, unless otherwise defined, all terms used in this specification shall be understood to have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Accordingly, unless explicitly defined in this specification, specific terms should not be interpreted in an overly ideal or formal sense. Additionally, terms such as "about," "substantially," etc., in this specification are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the said sense, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosed content in which precise or absolute values are mentioned to aid in understanding the invention. The present invention will be described in more detail below through examples. These examples are intended solely to explain the invention more specifically, and it will be obvious to those skilled in the art