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EP-4737399-A1 - BORON, SULPHUR COATED POSITIVE ELECTRODE ACTIVE MATERIAL FOR SECONDARY BATTERY

EP4737399A1EP 4737399 A1EP4737399 A1EP 4737399A1EP-4737399-A1

Abstract

A positive electrode active material particle according to one aspect of the present invention comprises sulfur (S) and boron (B), and when a ratio of a sulfur (S) concentration (ppm) to a boron (B) concentration (ppm) is denoted as S/B, it may be that 8≤S/B≤20.

Inventors

  • SHIN, Jaehoon
  • BAE, JIN HO
  • CHOI, JINHYEOK
  • KIM, JINKYU
  • SHIN, Sehee

Assignees

  • ECOPRO BM CO., LTD.

Dates

Publication Date
20260506
Application Date
20251022

Claims (15)

  1. A positive electrode active material particle, comprising: sulfur (S) and boron (B), wherein a ratio of a sulfur (S) concentration (ppm) to a boron (B) concentration (ppm) included in the positive electrode active material particle, denoted as S/B, is 8≤S/B≤20.
  2. The positive electrode active material particle of claim 1, wherein 10≤S/B≤15.
  3. The positive electrode active material particle of claim 1, wherein the boron (B) concentration (ppm) included in the positive electrode active material particle is from 100 ppm to 600 ppm.
  4. The positive electrode active material particle of claim 1, wherein the sulfur (S) concentration (ppm) included in the positive electrode active material particle is from 3,200 ppm to 5,000 ppm.
  5. The positive electrode active material particle of claim 1, wherein the positive electrode active material particle comprises a bulk region and a coating region, the coating region comprises sulfur (S) and boron (B), and the sulfur (S) and boron (B) included in the coating region are present on a part of a surface of the bulk region.
  6. The positive electrode active material particle of claim 5, wherein a sulfur (S) concentration (ppm) included in the coating region is greater than the sulfur (S) concentration (ppm) included in the positive electrode active material particle.
  7. The positive electrode active material particle of claim 1, wherein the positive electrode active material particle comprises Li 2 BO 3 .
  8. The positive electrode active material particle of claim 1, wherein the positive electrode active material particle comprises Li 2 SO 4 .
  9. The positive electrode active material particle of claim 1, further comprising a coating oxide comprising one or more selected from the group consisting of cobalt (Co), aluminum (Al), titanium (Ti), zirconium (Zr), magnesium (Mg), zinc (Zn), molybdenum (Mo), iron (Fe), nickel (Ni), barium (Ba), tungsten (W), yttrium (Y), niobium (Nb), and fluorine (F).
  10. The positive electrode active material particle of claim 1, wherein a specific surface area measured by a nitrogen adsorption BET method is from 0.42 m 2 /g to 0.5 m 2 /g.
  11. A method for manufacturing the positive electrode active material particle of claim 1, the method comprising: a step of mixing and heat-treating a positive electrode active material precursor and a lithium-containing compound to prepare a lithium composite oxide; a step of preparing a coating solution comprising a sulfur (S)-containing compound and a boron (B)-containing compound; and a step of spraying the prepared coating solution onto the prepared lithium composite oxide and heat-treating it.
  12. The method for manufacturing a positive electrode active material particle of claim 11, wherein a ratio of a sulfur (S) concentration (ppm) to a boron (B) concentration (ppm) included in the coating solution, denoted as 'S input /B input ', is 1.4≤S input /B input ≤5.0.
  13. The method for manufacturing a positive electrode active material particle of claim 11, wherein a heat treatment temperature in the step of spraying the prepared coating solution onto the prepared lithium composite oxide and heat-treating it is from 250°C to 350°C.
  14. The method for manufacturing a positive electrode active material particle of claim 11, further comprising: a step of coating the prepared lithium composite oxide with cobalt (Co), after the step of preparing the lithium composite oxide and before the step of spraying the prepared coating solution onto the prepared lithium composite oxide and heat-treating it.
  15. A positive electrode active material, comprising the positive electrode active material particle of claim 1.

Description

Technical Field The present invention relates to positive electrode active material particles and a positive electrode active material for a secondary battery comprising the same, and more particularly, to positive electrode active material particles that are mixed-coated with sulfur (S) and boron (B), and in which the coating content, coating conditions, and manufacturing method are controlled, and a positive electrode active material for a secondary battery comprising the same. Background With the development of portable mobile electronic devices such as smartphones, MP3 players, and tablet PCs, the demand for secondary batteries capable of storing electrical energy has been explosively increasing. In particular, with the emergence of electric vehicles, medium-to-large energy storage systems, and portable devices requiring high energy density, the demand for lithium secondary batteries is on the rise. As a lithium composite oxide included in the positive electrode active material, the material currently receiving the most attention is the lithium nickel manganese cobalt oxide Li(NixCoyMn2)O2 (where x, y, and z are the atomic fractions of the respective independent oxide composition elements, with 0<x≤1, 0<y≤1, 0<z≤1, and 0<x+y+z≤1). This positive electrode active material has the advantage of delivering high capacity because it is used at a higher voltage than LiCoO2, which has been actively researched and used as a positive electrode active material, and it has the advantage of being low-cost due to its relatively low Co content. However, such lithium composite oxides undergo volume changes accompanying the intercalation and deintercalation of lithium ions during charging and discharging. Problems arise where the primary particles of the lithium composite oxide undergo rapid volume changes during charging and discharging, cracks occur in the secondary particles due to repeated charging and discharging, or the crystal structure collapses or undergoes a phase transition. To compensate for these shortcomings, the demand for high-nickel positive electrode active materials, in which the nickel (Ni) content is high among the total metal content excluding lithium (Li), has begun to increase as a positive electrode active material for secondary batteries. Technical Problem Due to the high Li/M ratio during the manufacturing of the positive electrode active material, the amount of residual lithium remaining in the positive electrode active material after firing is high, which causes a gelation phenomenon during the preparation of the electrode slurry, leading to difficulties in cell manufacturing. Furthermore, although a washing process is introduced to remove the residual lithium present in the positive electrode active material during its manufacturing, there is a problem that the battery characteristics are degraded due to damage to the surface of the positive electrode active material particles during the washing process. Additionally, there is a problem that particle crystallinity is hindered and strain is induced by a stacking fault phenomenon caused by sulfur compounds, which are impurities existing inside the precursor particles originating from the positive electrode active material precursor particles. In particular, in high-nickel positive electrode active materials, the higher content of residual lithium present in the particles becomes more problematic, and the stability is reduced due to the high Ni content, resulting in a disadvantage of further decreased output. To solve the above problems, the present invention aims to manufacture a positive electrode active material that can improve both output and capacity characteristics by adopting a non-washing process during the manufacturing of the positive electrode active material to reduce surface damage to the positive electrode while significantly reducing residual lithium, through mixed coating with sulfur (S) and boron (B) and controlling the coating content, coating conditions, and manufacturing method. Furthermore, the present invention aims to manufacture a positive electrode active material that can significantly reduce the stacking fault phenomenon and strain and increase particle crystallinity by performing the mixing and coating of sulfur (S) and boron (B) through a semi-wet spray process, optimizing the mixing content ratio, and thereby causing internal impurities such as sulfur compounds that induce the stacking fault phenomenon to migrate to the surface of the positive electrode active material particles. Furthermore, the present invention aims to manufacture a positive electrode active material in which capacity, efficiency, and output characteristics are all improved compared to when sulfur (S) and boron (B) are used individually, by performing the mixing and coating of sulfur (S) and boron (B) through a semi-wet spray process in a non-washing process and optimizing the mixing content ratio. Technical Solution A positive electrode active