KR-102962315-B1 - ELECTRODE ACTIVE MATERIAL AND BATTERY

Abstract

In the present disclosure, the problem is solved by providing an electrode active material that contains Si elements and has pores inside primary particles, wherein the pores include a first pore with a pore diameter of 30 nm or more and 100 nm or less, and a second pore with a pore diameter of 1 nm or more and 5 nm or less, wherein when the amount of the first pore is A and the amount of the second pore is B, the ratio of A to B (A/B) is greater than 0.10 and less than 17.00.

Inventors

• 오타키 미츠토시
• 노세 마사후미

Assignees

• 도요타지도샤가부시키가이샤

Dates

Publication Date

20260508

Application Date

20250321

Priority Date

20240627

Claims (5)

1. It is an electrode active material containing Si elements and also having voids inside the primary particles, and As the above pore, it has a first pore having a pore diameter of 30 nm or more and 100 nm or less, and a second pore having a pore diameter of 1 nm or more and 5 nm or less, An electrode active material wherein, when the amount of the first void is A and the amount of the second void is B, the ratio of A to B (A/B) is 3 or more and 10 or less, and the amount of the first void A is 0.150cc/g or more and the amount of the second void B is 0.030cc/g or more.
2. delete
3. delete
4. In paragraph 1, Electrode active material having a silicon clatrate type II crystalline phase as the main phase.
5. A battery having a positive electrode active material layer, a negative electrode active material layer, and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, A battery in which the above negative electrode active material layer contains, as a negative electrode active material, an electrode active material described in claim 1 or claim 4.

Description

Electrode Active Material and Battery The present disclosure relates to an electrode active material and a battery. In recent years, the development of batteries has been actively pursued. For example, in the automotive industry, the development of batteries used in battery electric vehicles (BEVs) or hybrid electric vehicles (HEVs) is underway. Furthermore, Si is known as an active material (electrode active material) used in batteries. For example, Japanese Patent Publication No. 2023-044620 discloses an active material having a silicon clatrate type II crystalline phase, having pores inside the primary particles, and having a pore amount A of pores with a pore diameter of 100 nm or less that is greater than 0.15 cc/g and less than 0.40 cc/g. The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings. Figure 1a is a diagram illustrating the crystalline phase of an electrode active material. FIG. 1b is a diagram illustrating the crystalline phase of an electrode active material. FIG. 1c is a diagram illustrating the crystalline phase of an electrode active material. FIG. 2 is a schematic cross-sectional view illustrating a battery according to the present disclosure. Hereinafter, the electrode active material and battery of the present disclosure will be described in detail. A. Electrode active material The electrode active material in the present disclosure contains Si elements and also has pores inside the primary particles. In addition, the electrode active material in the present disclosure has, as the pores, a first pore with a pore diameter of 30 nm or more and 100 nm or less, and a second pore with a pore diameter of 1 nm or more and 5 nm or less, and when the amount of the first pore is A and the amount of the second pore is B, the ratio of A to B (A/B) is greater than 0.10 and less than 17.00. According to the present disclosure, the electrode active material has a predetermined first void and a second void, and furthermore, since the ratio of the amount of the first void A to the amount of the second void B is greater than 0.10 and less than 17.00, the volume change due to charging and discharging can be reduced. As described in the above Japanese Patent Publication No. 2023-044620, porous Si having pores inside primary particles is being considered to suppress volume change. In particular, it is believed that volume change caused by discharge can be uniformly mitigated by the presence of fine pores having a size (pore diameter) of 100 nm or less. Meanwhile, the inventors of the present invention have repeatedly examined the size of the pores and found that volume change can be further suppressed by adjusting the amount of relatively coarse pores (first pores) having a size of 30 nm or more and 100 nm or less, and the amount of relatively fine pores (second pores) having a size of 1 nm or more and 5 nm or less, among the fine pores, in a predetermined ratio. Although the first pores have a large capacity to absorb expansion and contraction, there is a risk that the reaction may become concentrated in that vicinity, and as a result, it is believed that if the proportion of the first pores is too high, the volume change of the active material as a whole may not be sufficiently suppressed. In contrast, it is believed that the presence of a second void allows for the homogenization of the reaction in the active material and enables the suppression of sufficient volume change in the entire active material. The electrode active material in the present disclosure contains Si elements and also has pores inside the primary particles. The electrode active material in the present disclosure corresponds to so-called porous Si (p-Si). The electrode active material in the present disclosure has a first pore having a pore diameter of 30 nm or more and 100 nm or less, and a second pore having a pore diameter of 1 nm or more and 5 nm or less as the pores. In addition, when the amount of the first pore is A and the amount of the second pore is B, the ratio of A to B (A/B) is greater than 0.10 and less than 17.00. The fact that the electrode active material has pores and has the first pore and the second pore can be confirmed by SEM (scanning electron microscope) observation. A/B may be 0.50 or greater, 1.00 or greater, 3.00 or greater, or 5.00 or greater. Additionally, A/B may be 16.00 or less, 15.00 or less, 13.00 or less, 10.00 or less, or 8.00 or less. The first porosity A and the second porosity B can be obtained, for example, by mercury porosimeter measurement, BET measurement, gas adsorption method, 3D-SEM, or 3D-TEM. The amount of the first void is not particularly limited as long as it satisfies A/B above. The amount of the first void may be, for example, 0.050cc/g or more, 0.100cc/g or more, or 0.150cc/g or more. Meanwhile, the amount of the first void may be, for example, 0.300cc/g o