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EP-4738467-A1 - NEGATIVE ELECTRODE ACTIVE MATERIAL AND SECONDARY BATTERY

EP4738467A1EP 4738467 A1EP4738467 A1EP 4738467A1EP-4738467-A1

Abstract

A negative electrode active material 10 according to the present disclosure includes: a carbon phase 1; and Si-Ni-containing particles 2 dispersed in the carbon phase 1. A percentage of Ni in the Si-Ni-containing particles 2 may be 0.01 mass% or more and 5.0 mass% or less. A secondary battery according to the present disclosure includes: a negative electrode including the negative electrode active material according to the present disclosure; a positive electrode; and a nonaqueous electrolyte.

Inventors

  • SAITO, YUSUKE
  • SUZUKI, Hirotetsu

Assignees

  • Panasonic Intellectual Property Management Co., Ltd.

Dates

Publication Date
20260506
Application Date
20240617

Claims (10)

  1. A negative electrode active material comprising: a carbon phase; and Si-Ni-containing particles dispersed in the carbon phase.
  2. The negative electrode active material according to claim 1, wherein a percentage of Ni in the Si-Ni-containing particles is 0.01 mass% or more and 5.0 mass% or less.
  3. The negative electrode active material according to claim 1, wherein the Si-Ni-containing particles comprise at least one selected from the group consisting of metallic Ni, a Ni oxide, and a Ni carbide.
  4. The negative electrode active material according to claim 3, wherein the Si-Ni-containing particles comprise metallic Ni.
  5. The negative electrode active material according to claim 1, wherein the Si-Ni-containing particles comprise crystalline silicon in which Ni atoms are dissolved to form a solid solution.
  6. The negative electrode active material according to claim 1, wherein the Si-Ni-containing particles comprise an amorphous phase.
  7. The negative electrode active material according to claim 1, wherein in an X-ray diffraction pattern obtained by X-ray diffraction measurement using Cu-Kα radiation, an X-ray diffraction peak derived from a Si(111) plane is present within a diffraction angle 2θ range from 28.30° to 28.40°.
  8. The negative electrode active material according to claim 1, wherein an average particle diameter of the Si-Ni-containing particles is 1 nm or more and 1,000 nm or less.
  9. The negative electrode active material according to claim 1, further comprising a coating layer coating a surface of the carbon phase, wherein the coating layer comprises carbon.
  10. A secondary battery comprising: a negative electrode comprising the negative electrode active material according to any one of claims 1 to 9; a positive electrode; and an electrolyte.

Description

TECHNICAL FIELD The present disclosure relates to a negative electrode active material and a secondary battery. BACKGROUND ART The use of composite materials containing silicon as negative electrode materials for increasing the capacity of lithium-ion batteries has recently been expected. For example, a negative electrode active material in which silicon is dispersed in a Li2Si2O5 matrix has been studied. In response to a demand for further increases in capacity, efficiency, and durability of lithium-ion batteries, composite materials containing silicon and a carbon material have been studied. Patent Literature 1 discloses a silicon/graphite/carbon composite containing graphite and nonaggregated, nanoscale silicon particles, wherein the silicon particles are embedded in a carbon matrix. CITATION LIST Patent Literature Patent Literature 1: JP 2017-506413 A SUMMARY OF INVENTION Technical Problem In conventional techniques, enhancement in the initial charge and discharge efficiency of a battery using a composite material containing silicon and a carbon material as an active material has been desired. Solution to Problem The negative electrode active material of the present disclosure includes: a carbon phase; andSi-Ni-containing particles dispersed in the carbon phase. Advantageous Effects of Invention The technique of the present disclosure can provide a negative electrode active material that can enhance the initial charge and discharge efficiency of a battery. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a cross-sectional view schematically showing the configuration of an example of a negative electrode active material according to Embodiment 1.FIG. 2 is a cross-sectional view schematically showing the configuration of another example of the negative electrode active material according to Embodiment 1.FIG. 3 is a cross-sectional view schematically showing the configuration of a secondary battery according to Embodiment 2.FIG. 4 is a graph showing X-ray diffraction patterns of negative electrode active materials of Example 1 and Comparative Example 1. DESCRIPTION OF EMBODIMENTS Embodiments of the present disclosure are described in detail below with reference to the drawings. The present disclosure is not limited to the following embodiments. (Embodiment 1) FIG. 1 is a cross-sectional view schematically showing the configuration of an example of a negative electrode active material according to Embodiment 1. The negative electrode active material 10 includes a carbon phase 1 and Si-Ni-containing particles 2 dispersed in the carbon phase 1. A negative electrode active material 10 is a composite particle that includes the carbon phase 1 and the Si-Ni-containing particles 2. The Si-Ni-containing particles 2 are particles that contain the element Si and the element Ni. Because the Si-Ni-containing particles 2 contain Ni, the Si-Ni-containing particles 2 exhibit enhanced electronic conductivity compared with that of silicon particles. That is, in the negative electrode active material 10, particles having enhanced electronic conductivity are dispersed in the carbon phase 1. According to the above configuration, the initial charge and discharge efficiency of a battery using the negative electrode active material 10 can be enhanced. The carbon phase 1 is a matrix that contains carbon, and includes, for example, a carbonaceous material. The carbonaceous material may be any carbon material capable of occluding lithium ions. The carbonaceous material may be amorphous. The carbon phase 1 may be composed of an amorphous carbonaceous material. Examples of the carbonaceous material include a material derived from pitch, amorphous carbon, carbon black, and a material derived from an organic polymer. Examples of the pitch include coal pitch and petroleum pitch, and the coal pitch is, for example, coal tar pitch. According to this configuration, it is possible to further stabilize, within the negative electrode active material 10, electrical connection between the Si-Ni-containing particles 2 and electrical connection between the Si-Ni-containing particles 2 and the carbonaceous material. The carbon phase 1 may include multiple types of carbonaceous materials. The percentage of carbon (C) in the negative electrode active material 10 may be 40 mass% or more and 80 mass% or less, 40 mass% or more and 60 mass% or less, or 40 mass% or more and 50 mass% or less. The percentage of C in the negative electrode active material 10 can be measured by a combustion-infrared absorption method using a carbon/sulfur analyzer. The Si-Ni-containing particles 2 are particles that contain Si and Ni. The Si-Ni-containing particles 2 may contain crystalline silicon. That is, the element Si in the Si-Ni-containing particles 2 may be crystalline silicon. In the Si-Ni-containing particles 2, Ni may be located within the Si-Ni-containing particles 2, and may be located on the surfaces of the Si-Ni-containing particles 2. For example, Ni may be dispersed w