JP-2026074580-A - Electrode manufacturing method

Abstract

[Problem] To provide a method for manufacturing electrodes that can increase battery capacity and suppress capacity degradation compared to conventional methods. [Solution] The method for manufacturing electrodes comprises a mixing step of mixing a main active material and a silicon-based active material, which constitute electrodes used in non-aqueous electrolyte secondary batteries, with dry powder; a dilution step of adding a liquid agent to the mixture mixed in the mixing step to produce a slurry; and a forming step of forming the slurry produced in the dilution step into electrodes . At least one of graphite, hard carbon, soft carbon, Li₄Ti₅O₁₂ , Sn, SnO, SnS, and Ge is used as the main active material, and at least one of Si, SiO, and SiC is used as the silicon-based active material. In the mixing step, the materials are mixed using a high-speed shear impact mixer having a first blade for mixing the materials overall and a second blade for applying shear force to the materials. [Selection Diagram] Figure 1

Inventors

• 岩崎 祥司
• 小泉 一郎
• 逵 隆伸
• 妹尾 博
• 向井 孝志
• 坂本 太地
• 池内 勇太

Assignees

• 株式会社ダルトン
• 国立研究開発法人産業技術総合研究所

Dates

Publication Date

20260507

Application Date

20241021

Claims (5)

1. A mixing step in which the main active material and the silicon-based active material, which constitute the electrodes used in a non-aqueous electrolyte secondary battery, are mixed as dry powders, A dilution step is performed in which a liquid agent is added to the mixture mixed in the above mixing step to produce a slurry. The process includes a forming step of forming the slurry produced in the dilution step onto the electrode, As the main active material, at least one of the following is used: graphite, hard carbon, soft carbon , Li₄Ti₅O₁₂ , Sn, SnO, SnS, and Ge. As the silicon-based active material, at least one of Si, SiO, and SiC is used. A method for manufacturing electrodes, comprising mixing the materials using a high-speed shear impact mixer having a first blade for mixing the materials overall and a second blade for applying a shear force to the materials.
2. The particle size of the main active material is 5 μm or more and 50 μm or less. The method for manufacturing an electrode according to claim 1, wherein the particle size of the silicon-based active material is 1/1000 or more and 1/50 or less of the particle size of the main active material.
3. The method for manufacturing an electrode according to claim 1, wherein a binder is added to the mixture in the dilution step.
4. The method for manufacturing an electrode according to claim 1, wherein, in the mixing step, the speed of the blade tip of the second blade is set to 5 m/s or more and 40 m/s or less.
5. The process includes a kneading step in which, after the mixing step and before the dilution step, a solvent is added to the mixture mixed in the mixing step and kneaded. A method for manufacturing an electrode according to any one of claims 1 to 4, wherein in the dilution step, the liquid agent is added to the mixture kneaded in the solid kneading step to produce the slurry.

Description

This invention relates to a method for manufacturing electrodes used in secondary batteries. Conventionally, when manufacturing electrodes for secondary batteries, a technique using graphite and silicon-based materials as active materials has been employed (see, for example, Patent Document 1). Japanese Patent Publication No. 2023-184480 A flowchart illustrating the manufacturing method of electrodes.(a) and (b) are schematic cross-sectional views showing a high-speed shear impact mixer.A schematic cross-sectional view showing a twin-axis planetary agitator mixer.This figure compares the initial Coulomb efficiency of the present electrode and a reference electrode.This figure compares the capacity and capacity retention rate of the electrode in this invention with that of a reference electrode. [Method for manufacturing electrodes] First, an electrode manufacturing method according to one embodiment of the present invention will be described with reference to Figure 1. The electrode according to this embodiment can be used as a negative electrode. The electrode manufacturing method according to this embodiment is used when constructing an electrode for a non-aqueous electrolyte secondary battery. As shown in Figure 1, the electrode manufacturing method comprises a mixing step (S01), a kneading step (S02), a dilution step (S03), and a forming step (S04). Each step will be described in order below. In this embodiment, the mixing step (S01) is a step of mixing the materials containing the main active material, silicon-based active material, conductive material, and thickener as dry powders. While the mixing step (S01) is a step of mixing the main active material and silicon-based active material as dry powders, as in this embodiment, dry powder materials such as conductive material and thickener can also be mixed simultaneously in the mixing step (S01) as appropriate. In this step, a high-speed shear impact mixer 10 is used, as shown in Figures 2(a) and (b). The high-speed shear impact mixer 10 has a mixing arm, which is a first blade 11 that mixes the materials overall, and a chopper blade, which is a second blade 12 that applies shear force to the materials. As shown in Figures 2(a) and 2(b), the high-speed shear impact mixer 10 in this embodiment is configured such that three first blades 11 and three second blades 12 rotate inside a mixing container 10a, which has a material input port 10b formed at its top. As shown in Figure 2(a), the first blades 11 rotate inside the mixing container 10a by the driving force of a motor (not shown) transmitted via a first shaft 11a. Similarly, the second blades 12 rotate inside the mixing container 10a by the driving force of a motor (not shown) transmitted via a second shaft 12a. In this embodiment of the high-speed shear impact mixer 10, the first blade 11 is configured to rotate in the first rotational direction, as shown by arrow R1 in Figure 2(b). On the other hand, the second blade 12 is configured to rotate in the opposite direction to the first rotational direction, as shown by arrow R2 in Figure 2(b). In this configuration of the high-speed shear impact mixer 10, the material is mixed thoroughly by the first blade 11, while a shear force is applied to the material by the second blade 12. The high-speed shear impact mixer 10, configured as described above, applies shear force to the material using the second blade 12 while mixing the material thoroughly with the first blade 11. In the high-speed shear impact mixer 10, the speed of the blade tip of the second blade 12 is set to between 5 m/s and 40 m/s. Next, in the solid kneading step (S02), the solvent is added to the mixture prepared in the mixing step (S01) and kneaded. Then, in the dilution step (S03), the liquid agent and binder are added to the mixture prepared in the solid kneading step (S02) to produce a slurry. Next, in the forming step (S04), the slurry produced in the dilution step (S03) is formed on an electrode. In the solid mixing step (S02) and the dilution step (S03) described above, a twin-screw planetary agitator mixer 20 can be used as shown in Figure 3. However, it is also possible to use other mixers, such as a self-rotating mixer, in these steps. As shown in Figure 3, the twin-axis planetary agitator mixer 20 in this embodiment is configured such that a first agitator 23a and a second agitator 23b, which are bent rods, rotate inside the mixing container 20a. As shown in Figure 3, the first agitator 23a and the second agitator 23b are connected to the rotating shaft 21 via a planetary gear mechanism 22. A driving force from a motor (not shown) is transmitted to the rotating shaft 21, causing the first agitator 23a and the second agitator 23b to rotate on their own axis while revolving around the axis. As described above, the electrode manufacturing method according to this embodiment involves a configuration in which dry powder mixing is performed using a high-speed shear impact mixer 10 equi