Search

CN-115440974-B - Positive active material, method of preparing the same, and rechargeable lithium battery including the same

CN115440974BCN 115440974 BCN115440974 BCN 115440974BCN-115440974-B

Abstract

Disclosed are a positive electrode active material, a method of preparing the same, and a rechargeable lithium battery including the same. The positive electrode active material includes a nickel-based composite metal oxide, which is a secondary particle in which a plurality of primary particles are aggregated, wherein the positive electrode active material includes a core and a shell, the primary particles of the shell are coated with a manganese-containing nickel-based composite metal oxide, and the manganese-containing nickel-based composite metal oxide has a layered structure.

Inventors

  • Kong Yongshan
  • AN JIRONG
  • Quan Shanying
  • Jin Menzhou
  • LI DOUJUN
  • Quan Daoyu
  • HONG QIZHU

Assignees

  • 三星SDI株式会社
  • 三星SDI株式会社

Dates

Publication Date
20260421
Application Date
20220301
Priority Date
20210601

Claims (12)

  1. 1. A positive electrode active material comprising: A nickel-based composite metal oxide which is a secondary particle in which a plurality of primary particles are aggregated, Wherein the secondary particles comprise a core and a shell, wherein the core does not comprise manganese, The surface of the primary particles of the shell is coated with a manganese-containing nickel-based composite metal oxide, The manganese-containing nickel-based composite metal oxide has a layered structure, Wherein the content of manganese in the positive electrode active material is less than 1.5mol%, and Wherein the manganese-containing nickel-based composite metal oxide is represented by chemical formula 1: [ chemical formula 1] LiNi 1-x-y-z Co x Mn y M z O 2 Wherein, in the chemical formula 1, X is more than or equal to 0 and less than or equal to 0.5,0.001, y is more than or equal to 0.015,0 and less than or equal to 0.3, and M is at least one metal element selected from Ni, al, cr, fe, V, mg, ti, zr, nb, mo, W, cu, zn, ga, in, sn, la, B, ta, pr, si, ba and Ce.
  2. 2. The positive electrode active material according to claim 1, wherein a manganese concentration has a concentration gradient, wherein the manganese concentration increases from an inside to a surface of the primary particles of the shell.
  3. 3. The positive electrode active material according to claim 1, wherein the manganese-containing nickel-based composite metal oxide is in an island form or a fine nanoparticle form on the surface of the primary particles of the shell.
  4. 4. The positive electrode active material according to claim 1, wherein the thickness of the shell is less than or equal to 2 μm.
  5. 5. The positive electrode active material according to claim 1, wherein the positive electrode active material has a particle diameter of 8 μm to 18 μm.
  6. 6. The positive electrode active material according to claim 1, wherein the positive electrode active material further comprises LiMnO 2 on the surface of the primary particles of the shell.
  7. 7. A method of preparing the positive electrode active material according to any one of claims 1 to 6, comprising: adding a water-soluble solvent to a nickel-based composite metal compound and manganese hydroxide to prepare a mixture, wherein the nickel-based composite metal compound is a secondary particle in which a plurality of primary particles are aggregated, and the secondary particle includes a core and a shell, Reacting the mixture at 40 to 100 ℃ for 30 minutes to 1 hour to coat grain boundaries between the primary particles of the shell of the nickel-based composite metal compound with a manganese-containing nickel-based composite metal oxide, and The coated resulting material is mixed with a lithium source, and fired, Wherein the manganese content in the manganese-containing nickel-based composite metal oxide is less than 1.5mol% based on the total mole number of metals other than lithium of the manganese-containing nickel-based composite metal oxide.
  8. 8. The method of claim 7, wherein the nickel-based composite metal compound is one of a nickel-based composite metal oxide and a nickel-based composite metal hydroxide.
  9. 9. The method of claim 7, wherein the water-soluble solvent comprises any one of NaOH, KOH, and mixtures thereof.
  10. 10. The method of claim 7, wherein the mixture is dried at 100 ℃ to 200 ℃ after reacting the mixture at 40 ℃ to 100 ℃ for 30 minutes to 1 hour.
  11. 11. The method of claim 7, wherein the firing temperature is 600 ℃ to 800 ℃ and the firing time is 8 hours to 30 hours or 8 hours to 24 hours.
  12. 12. A rechargeable lithium battery comprising: A positive electrode comprising the positive electrode active material according to any one of claims 1 to 6 or a positive electrode active material produced by the method for producing a positive electrode active material according to any one of claims 7 to 11; A negative electrode including a negative electrode active material, and An electrolyte.

Description

Positive active material, method of preparing the same, and rechargeable lithium battery including the same Technical Field Disclosed are a positive active material for a rechargeable lithium battery, a method of preparing the same, and a rechargeable lithium battery including the same. Background In order to meet the miniaturization and high performance of various devices, rechargeable lithium batteries are becoming increasingly important in terms of high energy density and miniaturization and weight saving. In addition, high capacity and high temperature stability of the rechargeable lithium battery and safety at high voltage become important for application to electric vehicles and the like. Various positive electrode active materials have been studied to realize rechargeable lithium batteries for such applications. Nickel-based lithium transition metal oxides including nickel, cobalt, manganese, etc. simultaneously provide high discharge capacity per unit weight as compared to conventional LiCoO 2, but have relatively low capacity and discharge capacity per unit volume due to low packing density. In addition, the safety of the nickel-based lithium transition metal oxide may be deteriorated when driven at a high voltage. Accordingly, a method for improving the structural stability and cycle life of nickel-based lithium transition metal oxides is needed. Disclosure of Invention One embodiment provides a positive electrode active material having improved structural stability and effectively improving the cycle life of a rechargeable lithium battery. Another embodiment provides a method of preparing a positive electrode active material. Another embodiment provides a rechargeable lithium battery having improved charge/discharge efficiency and cycle life characteristics by employing a positive electrode including a positive electrode active material. One embodiment provides a positive electrode active material including a nickel-based composite metal oxide, the nickel-based composite metal oxide being secondary particles in which a plurality of primary particles are aggregated, wherein the positive electrode active material (e.g., the nickel-based composite metal oxide) includes a core and a shell, the primary particles of the shell are coated with a manganese-containing nickel-based composite metal oxide, and the manganese-containing nickel-based composite metal oxide has a layered structure. The core may not include manganese. The manganese concentration may have a concentration gradient in which the manganese concentration increases from the interior to the surface of the primary particles of the shell. The coating of manganese coated on the shell (e.g., on the primary particles of the shell) may be in island form or in the form of fine nanoparticles. For example, the content of manganese in the positive electrode active material may be less than about 1.5mol% with respect to the manganese-containing nickel-based composite metal oxide of the shell. The shell may have a thickness of less than or equal to about 2 μm. The positive electrode active material may have a particle size of about 8 μm to about 18 μm. The manganese-containing nickel-based composite metal oxide can be represented by chemical formula 1: [ chemical formula 1] LiNi1-x-y-zCoxMnyMzO2 In the chemical formula 1, the chemical formula is shown in the drawing, X is more than or equal to 0 and less than or equal to 0.5,0.001, y is more than or equal to 0.015,0 and less than or equal to 0.3, and M is at least one metal element selected from Ni, al, cr, fe, V, mg, ti, zr, nb, mo, W, cu, zn, ga, in, sn, la, B, ta, pr, si, ba and Ce. LiMnO 2 may be included on the surface of the primary particles of the shell. In an embodiment, the positive electrode active material may be prepared by the following method: Adding a water-soluble solvent to the nickel-based complex metal compound and manganese hydroxide to prepare a mixture, Reacting the mixture at about 40 ℃ to about 100 ℃ for about 30 minutes to about 1 hour to coat the primary particles of the shell with manganese, and The coated resulting material is mixed with a lithium source and fired. The nickel-based composite metal compound may be a nickel-based composite metal oxide or a nickel-based composite metal hydroxide. The water-soluble solvent may include any one of NaOH, KOH, and mixtures thereof. After the mixture is reacted at about 40 ℃ to about 100 ℃ for about 30 minutes to about 1 hour, the mixture may be dried at about 100 ℃ to about 200 ℃, e.g., the method may further comprise the step of drying the mixture at about 100 ℃ to about 200 ℃ after the step of reacting the mixture. The firing temperature may be about 600 ℃ to about 800 ℃ and the firing time may be about 8 hours to about 30 hours or about 8 hours to about 24 hours. Another embodiment provides a rechargeable lithium battery including a positive electrode active material, a negative electrode including a negative electrode active m