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JP-2026075456-A - Positive electrode active material, battery, and method for manufacturing a positive electrode active material

JP2026075456AJP 2026075456 AJP2026075456 AJP 2026075456AJP-2026075456-A

Abstract

[Challenge] Improvement of rate characteristics. [Solution] A positive electrode active material comprising a plurality of secondary particles, each of the plurality of secondary particles comprising a plurality of primary particles, each of the plurality of primary particles comprising an olivine-type phosphate compound, wherein in a scanning electron microscope image of the secondary particles, the proportion of primary particles having a contact angle of 90° or less among the primary particles having a maximum Ferret diameter of 100 nm or more is 40% or more. [Selection Diagram] Figure 1

Inventors

  • 小坂 大地
  • 江口 達哉
  • 君島 健之

Assignees

  • トヨタ自動車株式会社
  • 株式会社豊田自動織機

Dates

Publication Date
20260508
Application Date
20241022

Claims (7)

  1. It is a positive electrode active material, The positive electrode active material includes a plurality of secondary particles, Each of the plurality of secondary particles includes a plurality of primary particles, Each of the plurality of primary particles contains an olivine-type phosphate compound, In the scanning electron microscope image of the secondary particle, Of the primary particles having a maximum Ferret diameter of 100 nm or more, the proportion of primary particles having a contact angle of 90° or less is 40% or more. Cathode active material.
  2. In the scanning electron microscope image of the secondary particle, Of the primary particles having a maximum Ferret diameter of 100 nm or more, the proportion of primary particles having a contact angle of 90° or less is 75% or more. The positive electrode active material according to claim 1.
  3. The olivine-type phosphate compound is manganese iron lithium phosphate. The positive electrode active material according to claim 1.
  4. A positive electrode active material comprising the positive electrode active material according to any one of claims 1 to 3, battery.
  5. Having a bipolar structure, The battery according to claim 4.
  6. (a) Forming a slurry by mixing a manganese compound, a lithium-1 compound, a phosphoric acid compound, and a solvent. (b) Drying the slurry to form first precursor particles, (c) Mixing the first precursor particles and the second lithium compound and subjecting them to a first heat treatment to form second precursor particles. (d) Producing an olivine-type phosphate compound by subjecting the second precursor particles to a second heat treatment, A method for manufacturing a positive electrode active material.
  7. The duration of the first heat treatment is 2 hours or more and 4 hours or less. The temperature of the second heat treatment is 600°C or higher and 750°C or lower. A method for producing a positive electrode active material according to claim 6.

Description

This disclosure relates to a positive electrode active material, a battery, and a method for manufacturing a positive electrode active material. International Publication No. 2021/153007 (Patent Document 1) discloses a secondary battery electrode active material having an olivine-type crystal structure and a carbon layer on its surface, with a crystallite size of 60 nm or less. International Publication No. 2021/153007 This is a schematic cross-sectional view showing a portion of the secondary particles in this embodiment.This is a conceptual diagram showing secondary particles in this embodiment.This is a schematic flowchart illustrating the method for producing the positive electrode active material in this embodiment.This is a schematic perspective view of the battery in this embodiment.This is a schematic cross-sectional view along the line VI-VI in Figure 4.This table shows the manufacturing conditions and experimental results for the positive electrode active material in the examples. <Terms and Phrases> "Equipped with,""includes,""possesses," and variations thereof are open-ended expressions. Configurations expressed in an open-ended manner may or may not include additional elements in addition to the essential elements. The statement "consists of" is a closed expression. However, even configurations expressed in a closed manner may include additional elements that are usually incidental impurities or irrelevant to the subject technology. The statement "substantially consists of..." is a semi-closed expression. In configurations expressed in a semi-closed manner, the addition of elements that do not substantially affect the basic and novel characteristics of the subject technology is permitted. Expressions like "may do" or "may be" are used in a permissive sense ("having the possibility") rather than in an obligatory sense ("must do"). Unless otherwise specified, the order in which the steps, actions, and operations included in each method are executed is not limited to the order in which they are described. For example, multiple steps may occur simultaneously. For example, multiple steps may occur one after the other. Expressions such as "first," "second," etc., are used solely to distinguish between multiple elements. These expressions do not in any way limit the elements to which they are attached. They are unrelated, for example, to the order or importance of the elements to which they are attached. For example, the expression "at least one of A and B" includes both "A or B" and "A and B." "At least one of A and B" can also be written as "A and/or B." Geometric terms should not be interpreted strictly. Examples of geometric terms include "parallel," "perpendicular," and "orthogonal." For example, direction, angle, distance, etc., may be relatively distorted within a range where substantially the same or similar function is achieved. Geometric terms may include tolerances, errors, etc., in design, operation, and manufacturing. Dimensional relationships in each figure may not match actual dimensional relationships. Dimensional relationships in each figure may be modified to aid the reader's understanding. For example, length, width, thickness, etc., may be changed. Some components may be omitted. Elements described in the singular form may also include plural forms unless otherwise specified. For example, "particle" may refer to multiple particles, a collection of particles, or a granular material. Numerical ranges such as "m to n%" include upper and lower limits unless otherwise specified. That is, "m to n%" indicates a numerical range of "m% or more and n% or less." Furthermore, "m% or more and n% or less" includes "greater than m% and less than n%." "Greater than or equal to" and "less than or equal to" are represented by the equals sign inequality signs "≦" and "≧." "Greater than" and "less than" are represented by the inequality signs without an equals sign "＜" and ＞." A numerical value arbitrarily selected from within the numerical range may be used as a new upper or lower limit. For example, a new numerical range may be established by arbitrarily combining a numerical value within the range with a numerical value described in another part of this specification, in a table, in a figure, etc. All numerical values are modified by the term "approximately." "Approximately" can mean, for example, ±5%, ±3%, ±1%, etc. All numerical values may be approximations that vary depending on the application of the technology in question. All numerical values may be expressed with significant figures. Unless otherwise specified, measured values may be the average of multiple measurements. The number of measurements may be three or more, five or more, or ten or more. Generally, the reliability of the average is expected to improve with a larger number of measurements. Measured values may be rounded to the nearest significant figure. Measured values may include errors such as those associated with the detection