WO-2026095055-A1 - NEGATIVE ELECTRODE ACTIVE MATERIAL, METHOD FOR PRODUCING NEGATIVE ELECTRODE ACTIVE MATERIAL, AND BATTERY

Abstract

A negative electrode active material according to the present disclosure comprises composite particles 10 which include a carbon phase 1 and silicon particles 2 dispersed in the carbon phase 1, wherein in a solid-state 29 Si-NMR spectrum, the area ratio of a peak A having a peak top in the range of a -30 ppm to -7.5 ppm chemical shift to the total area of all detected peaks is more than 7.6%.

Inventors

• BADAR SAIFULLAH
• HIRAI TAKEHIKO

Assignees

• パナソニックＩＰマネジメント株式会社

Dates

Publication Date

20260507

Application Date

20251031

Priority Date

20241031

Claims (10)

1. Carbon phase and, Silicon particles dispersed in the carbon phase, Composite particles comprising, In the solid- state Si-NMR spectrum, the area ratio of peak A, whose peak top is within the chemical shift range of -30 ppm or more and -7.5 ppm or less, to the total area of all detected peaks, exceeds 7.6%. Negative electrode active material.
2. The area ratio of the aforementioned peak A is 10% or more. The negative electrode active material according to claim 1.
3. The area ratio of the aforementioned peak A is 50% or less. The negative electrode active material according to claim 1.
4. In the X-ray diffraction pattern obtained by X-ray diffraction measurement using Cu-Kα rays of the negative electrode active material, the full width at half maximum of the diffraction peaks originating from the Si(111) plane that appear in the range of diffraction angle 2θ of 28.0° or more and 28.7° or less is 1.8° or more. The negative electrode active material according to claim 1.
5. The aforementioned full width at half maximum is 7.0° or less. The negative electrode active material according to claim 4.
6. Further containing Cl, The negative electrode active material according to claim 1.
7. (I) preparing a porous carbon skeleton, and (II) using a silicon precursor gas as a raw material gas, precipitating silicon particles in the pores of the porous carbon skeleton by chemical vapor deposition at a temperature exceeding 500°C and not exceeding 700°C. A method for producing a negative electrode active material, including the material itself.
8. In (II) above, the silicon particles are deposited in the pores of the porous carbon skeleton by chemical vapor deposition at a temperature of 530°C or higher and 650°C or lower. A method for producing a negative electrode active material according to claim 7.
9. The aforementioned precursor gas includes dichlorosilane gas. A method for producing a negative electrode active material according to claim 7.
10. A negative electrode comprising the negative electrode active material according to any one of claims 1 to 6, Positive electrode and, Electrolytes, A battery equipped with a battery.

Description

Negative electrode active material, method for manufacturing negative electrode active material, and battery This disclosure relates to a negative electrode active material, a method for producing a negative electrode active material, and a battery. In recent years, secondary batteries such as lithium-ion batteries have been widely used in applications requiring high capacity, such as automotive and energy storage. The electrodes that make up such batteries have a significant impact on their performance. Therefore, various studies have been conducted on electrodes. It is known that silicon (Si)-containing negative electrode active materials are effective in increasing the capacity of batteries. However, negative electrode active materials containing Si undergo large volume changes during charging and discharging, leading to the disruption of conductive paths with surrounding active materials due to repeated charging and discharging, resulting in capacity degradation with each charge-discharge cycle. Therefore, Patent Documents 1 and 2 propose negative electrode active materials containing Si that can improve cycle characteristics. Specifically, Patent Documents 1 and 2 propose negative electrode active materials containing composite particles in which silicon is attached within the pores of a carbon material having predetermined pore sizes. Figure 1 is a cross-sectional view showing the schematic configuration of the composite particles contained in the negative electrode active material according to Embodiment 1.Figure 2 is a cross-sectional view showing a schematic configuration of a modified example of the composite particles contained in the negative electrode active material according to Embodiment 1.Figure 3 is a flowchart showing an example of a method for producing a negative electrode active material according to Embodiment 1.Figure 4 is a cross-sectional view showing the schematic configuration of a battery according to Embodiment 2. The embodiments of this disclosure will be described in detail below with reference to the drawings. This disclosure is not limited to the embodiments described below. (Embodiment 1) The negative electrode active material according to Embodiment 1 comprises composite particles. Figure 1 is a cross-sectional view showing the schematic configuration of the composite particles 10 provided in the negative electrode active material according to Embodiment 1. The composite particles 10 are particles comprising a carbon phase 1 and silicon particles 2 dispersed in the carbon phase 1. In the solid 29 Si-NMR spectrum of the negative electrode active material according to Embodiment 1, the area ratio of peak A having a peak top within the range of chemical shift -30 ppm or more and -7.5 ppm or less to the total area of all detected peaks exceeds 7.6%. In the negative electrode active material according to Embodiment 1, since the silicon particles 2 are dispersed within the carbon phase 1, the expansion of the silicon particles 2 during charging is mitigated by the carbon phase 1. That is, the negative electrode active material according to Embodiment 1 has a configuration comprising a composite particle 10 containing the carbon phase 1 and the silicon particles 2 dispersed within the carbon phase 1, thereby minimizing expansion during charging. As described above, the negative electrode active material according to Embodiment 1 further has a configuration in which, in the solid 29 Si-NMR spectrum, the area ratio of peak A having a peak top within the range of chemical shift -30 ppm or more and -7.5 ppm or less to the total area of all detected peaks exceeds 7.6%. Here, in the solid 29 Si-NMR spectrum, peak A having a peak top within the range of chemical shift -30 ppm or more and -7.5 ppm or less is presumed to be a peak originating from SiO₂C₂ . In a negative electrode active material comprising composite particles 10 including a carbon phase 1 and silicon particles 2 dispersed in the carbon phase 1, it is presumed that O-Si-C bonding can occur near the interface between the carbon phase 1 and the silicon particles 2. Therefore, it is considered that the silicon particles 2 are fixed to the carbon phase 1 by O-Si-C bonding, and the expansion of the negative electrode active material due to the expansion of the silicon particles 2 during charging can be further suppressed. The negative electrode active material according to Embodiment 1 has an area ratio of peak A, which is estimated to be a peak originating from SiO₂C₂ , that exceeds 7.6%, thereby further suppressing expansion during charging. Consequently, the negative electrode active material according to Embodiment 1 can further suppress cracks and fractures in the composite particles 10 caused by stress associated with the expansion and contraction of silicon particles 2 during charging and discharging, thereby improving the charge-discharge cycle characteristics of the battery. In this specification, the reference for th