JP-2026076137-A - Cathode active material for secondary batteries

Abstract

[Problem] To provide a positive electrode active material that reduces residual lithium present in positive electrode active material particles and improves capacity, efficiency, and output characteristics. [Solution] The positive electrode active material particles according to one aspect of the present invention contain sulfur (S) and boron (B), and when the ratio of sulfur (S) concentration (ppm) to boron (B) concentration (ppm) is S/B, the ratio 8 ≤ S/B ≤ 20. [Selection Diagram] Figure 1

Inventors

• シン，ジェフン
• ぺ，ジンホ
• チェ，ジンヒョク
• キム，ジンキュ
• シン，セヒ

Assignees

• エコプロ ビーエム カンパニー リミテッド

Dates

Publication Date

20260511

Application Date

20251023

Priority Date

20241023

Claims (15)

1. The positive electrode active material particles contain sulfur (S) and boron (B). When the ratio of sulfur (S) concentration (ppm) to boron (B) concentration (ppm) in the positive electrode active material particles is S/B, then 8 ≤ S/B ≤ 20.
2. The positive electrode active material particles according to claim 1, wherein 10 ≤ S/B ≤ 15.
3. The positive electrode active material particles according to claim 1, wherein the boron (B) concentration (ppm) contained in the positive electrode active material particles is 100 ppm to 600 ppm.
4. The positive electrode active material particles according to claim 1, wherein the sulfur (S) concentration (ppm) contained in the positive electrode active material particles is 3,200 ppm to 5,000 ppm.
5. The positive electrode active material particle according to 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) contained within the coating region are present on a portion of the surface of the bulk region.
6. The positive electrode active material according to claim 5, wherein the sulfur (S) concentration (ppm) contained within the coating region is greater than the sulfur (S) concentration (ppm) contained within the positive electrode active material particles.
7. The positive electrode active material particles according to claim 1, wherein the positive electrode active material particles contain Li2BO3 .
8. The positive electrode active material particles according to claim 1, wherein the positive electrode active material particles contain Li₂SO₄ .
9. The positive electrode active material particle according to claim 1, further comprising a coating oxide containing one or more selected from 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 particles according to claim 1, wherein the specific surface area measured by the nitrogen adsorption BET method is 0.42 m² /g to 0.5 m² /g.
11. A method for producing positive electrode active material particles according to claim 1, comprising the steps of: producing a lithium composite oxide by mixing and heat-treating a positive electrode active material precursor and a lithium-containing compound; producing a coating solution containing a sulfur (S)-containing compound and a boron (B)-containing compound; and spraying and heat-treating the produced coating solution onto the produced lithium composite oxide.
12. A method for producing positive electrode active material particles, according to claim 11, wherein when the ratio of sulfur (S) concentration (ppm) to boron (B) concentration (ppm) contained in the coating liquid is defined as "S input/B input", the ratio is 1.4 ≤ S input/B input ≤ 5.0.
13. A method for producing positive electrode active material particles, according to claim 11, wherein the heat treatment temperature in the step of spraying the manufactured coating liquid onto the manufactured lithium composite oxide is 250°C to 350°C.
14. A method for producing positive electrode active material particles, further comprising the step of coating the produced lithium composite oxide with cobalt (Co) after the step of producing the lithium composite oxide and before the step of spraying the produced coating solution onto the produced lithium composite oxide and heat-treating it; according to claim 11.
15. A positive electrode active material comprising positive electrode active material particles according to claim 1.

Description

This invention relates to positive electrode active material particles and positive electrode active materials for secondary batteries containing the same, and more particularly to positive electrode active material particles coated with a mixture of sulfur (S) and boron (B), with controlled coating content, coating conditions, and manufacturing method, and positive electrode active materials for secondary batteries containing the same. The development of portable mobile electronic devices such as smartphones, MP3 players, and tablet PCs has led to an explosive increase in demand for rechargeable batteries that can store electrical energy. In particular, the emergence of electric vehicles, medium- and large-scale energy storage systems, and portable devices requiring high energy density has led to increased demand for lithium-ion batteries. The lithium composite oxide that has recently attracted the most attention as a positive electrode active material is lithium nickel manganese cobalt oxide Li(Ni x Co y Mn 2 )O 2 (where x, y, and z are the atomic fractions of independent oxide constituent elements, with 0 < x ≤ 1, 0 < y ≤ 1, 0 < z ≤ 1, and 0 < x + y + z ≤ 1). This cathode active material has the advantage of producing high capacitance because it is used at higher voltages than LiCoO2 , which has been actively researched and used as a cathode active material until now, and it also has the advantage of being inexpensive because it has a relatively low Co content. However, such lithium-compound oxides undergo volume changes during charging and discharging due to the intercalation and deintercalation of lithium ions. During charging and discharging, the primary particles of the lithium composite oxide undergo rapid volume changes, and repeated charging and discharging can cause cracks in the secondary particles, as well as collapse of the crystal structure or a phase transition of the crystal structure. To compensate for these shortcomings, demand for high-nickel cathode active materials, which have a high nickel (Ni) content among all metals excluding lithium (Li), has begun to increase as cathode active materials for secondary batteries. Figure 1 shows SEM images of particle surfaces according to the embodiments and comparative examples of the present invention.Figure 2 shows an SEM-EDS image of a particle cross-section produced by the manufacturing method of the present invention.Figure 3 shows a SEM-EDS image of the particle surface produced by the manufacturing method of the present invention.Figure 4 is an SEM-EDS image of a particle cross-section relating to Example 1 of the present invention. Expressions such as "includes" as used herein should be understood as open-ended terms that may include other components. As used herein, "preferred" and "preferred" refer to embodiments of the present invention that can provide predetermined advantages under predetermined conditions. However, this does not intend to exclude other embodiments from the scope of the present invention. Furthermore, singular forms used in the specification and attached claims may be intended to include plural forms unless otherwise specified in the context. In other words, the technical characteristics of any one particle may also represent the technical characteristics of multiple particles, and can be intended to represent the average technical characteristics of multiple particles. The numerical ranges used herein include lower and upper limits and all values within those limits, increments logically derived from the form and width of the defined range, all doubly limited values, and all possible combinations of upper and lower limits of numerical ranges limited in different forms. Unless otherwise specified herein, values outside the defined numerical range, which may occur due to experimental error or rounding, are included within that range. The term "layer" includes not only shapes that are formed across the entire surface when observed in a plan view, but also shapes that are formed on only a portion of the surface. The meanings of "≦", "greater than or equal to", or "less than or equal to" as used herein may be replaced with the meanings of "<", "greater than", or "less than". On the other hand, the technical features described below relate to one embodiment that achieves the effects intended by the present invention as described above. In other words, a positive electrode active material according to one aspect of the present invention, by incorporating the technical features of one aspect described below, can reduce residual lithium in the particles, remove sulfur impurities within the particles originating from the precursor, increase crystallinity, and improve the capacity, efficiency, and output characteristics of a secondary battery. This invention relates to positive electrode active material particles for secondary batteries and a positive electrode active material containing a plurality of such particles. The secon