CN-122003734-A - Negative electrode for nonaqueous electrolyte power storage element and nonaqueous electrolyte power storage element

Abstract

The negative electrode for a nonaqueous electrolyte power storage element according to one aspect of the present invention includes a negative electrode active material layer containing a negative electrode active material including a material alloyed with lithium element, a solid electrolyte, and a conductive agent including a single-layer carbon nanotube.

Inventors

• Kikuchi Shiakifumi
• ASHIDA YUYA

Assignees

• 株式会社杰士汤浅国际

Dates

Publication Date

20260508

Application Date

20240918

Priority Date

20231012

Claims (14)

1. 1. A negative electrode for a nonaqueous electrolyte electricity storage element includes a negative electrode active material layer containing a negative electrode active material, a solid electrolyte, and a conductive agent, The negative electrode active material contains a material alloyed with lithium, The conductive agent comprises a single-layer carbon nanotube.
2. 2. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1, wherein a content of the single-layer carbon nanotube in the negative electrode active material layer is 0.1 to 3 mass%.
3. 3. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or 2, wherein a content of the fibrous conductive agent in the conductive agent is 90 mass% or more.
4. 4. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or 2, wherein a content of the single-layer carbon nanotube in the negative electrode active material layer is 0.3 mass% or more.
5. 5. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or 2, wherein the substance alloyed with a lithium element does not have a three-dimensional network structure.
6. 6. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or2, wherein an average pore diameter of the substance alloyed with a lithium element is 30nm or less.
7. 7. The negative electrode for a nonaqueous electrolyte electricity storage element according to claim 1 or2, wherein an average particle diameter of the substance alloyed with a lithium element is 0.6 μm or more.
8. 8. The negative electrode for a nonaqueous electrolyte electricity storage element according to claim 1 or2, wherein an average particle diameter of the substance alloyed with a lithium element is 1.5 μm or more.
9. 9. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or 2, wherein the BET specific surface area of the substance alloyed with a lithium element is 8.0m 2 /g or less.
10. 10. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or 2, wherein a content of the substance alloyed with a lithium element in the negative electrode active material layer is 45 mass% or less.
11. 11. The negative electrode for a nonaqueous electrolyte storage element according to claim 1 or 2, wherein the conductive agent further comprises at least one selected from particulate conductive agents and fibrous conductive agents having an average diameter of 120nm or more.
12. 12. The negative electrode for a nonaqueous electrolyte power storage element according to claim 1 or 2, wherein a content of the single-layer carbon nanotube in the conductive agent is 50 mass% or more.
13. 13. A nonaqueous electrolyte electricity storage element comprising the negative electrode for nonaqueous electrolyte electricity storage element according to claim 1 or 2.
14. 14. The nonaqueous electrolyte storage element according to claim 13, which is an all-solid storage element.

Description

Negative electrode for nonaqueous electrolyte power storage element and nonaqueous electrolyte power storage element Technical Field The present invention relates to a negative electrode for a nonaqueous electrolyte power storage element and a nonaqueous electrolyte power storage element. Background Nonaqueous electrolyte secondary batteries, typified by lithium ion secondary batteries, are widely used in electronic devices such as personal computers and communication terminals, automobiles, and the like because of their high energy density. The nonaqueous electrolyte secondary battery is generally configured to have a pair of electrodes electrically isolated from each other and a nonaqueous electrolyte interposed between the electrodes, and to be charged and discharged by exchanging charge transport ions such as lithium ions between the electrodes. As a power storage element other than the nonaqueous electrolyte secondary battery, a capacitor such as a lithium ion capacitor or an electric double layer capacitor is widely used. In recent years, a nonaqueous electrolyte power storage element has been proposed in which a solid electrolyte such as a sulfide solid electrolyte, an oxide solid electrolyte, or a polymer solid electrolyte is used as a nonaqueous electrolyte instead of a nonaqueous electrolyte solution in which an electrolyte salt is dissolved in a liquid such as a nonaqueous solvent. In addition, a silicon material (silicon-based active material) as a negative electrode active material is expected to be a promising negative electrode active material because of its higher energy density and the like as compared with a carbon material (carbon-based active material) such as graphite. Patent document 1 describes an all-solid battery having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, the negative electrode layer containing a silicon material as a negative electrode active material. Materials alloyed with lithium other than silicon-based active materials are also known as negative electrode active materials. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2021-0825514 Disclosure of Invention A substance alloyed with lithium such as a silicon-based active material is a negative electrode active material having a large volume change due to charge and discharge. On the other hand, in the nonaqueous electrolyte power storage element, coulombic efficiency, which is a ratio of discharge capacity to charge capacity, is preferably high. However, in a nonaqueous electrolyte power storage element using a negative electrode including a negative electrode active material having a large volume change accompanying charge and discharge and a solid electrolyte, there is a problem that coulombic efficiency (first coulombic efficiency) is low during first charge and discharge. In addition, according to the findings of the inventors, the difference in coulombic efficiency between a nonaqueous electrolyte power storage element using a substance alloyed with lithium element as a negative electrode active material and a nonaqueous electrolyte power storage element using another negative electrode active material (for example, graphite) is small in the charge and discharge of the second and subsequent times. The first coulomb efficiency is preferably high in terms of increasing the capacity of the nonaqueous electrolyte storage element, since many charge transport ions, i.e., lithium ions, which do not contribute to the charge and discharge of the second and subsequent times, are generated by the first charge. The present invention provides a negative electrode for a nonaqueous electrolyte power storage element, which contains a substance alloyed with a lithium element and a solid electrolyte and can improve the first coulomb efficiency of the nonaqueous electrolyte power storage element, and a nonaqueous electrolyte power storage element provided with such a negative electrode for a nonaqueous electrolyte power storage element. The negative electrode for a nonaqueous electrolyte power storage element according to one aspect of the present invention includes a negative electrode active material layer containing a negative electrode active material including a material alloyed with lithium element, a solid electrolyte, and a conductive agent including a single-layer carbon nanotube. The nonaqueous electrolyte power storage element according to another aspect of the present invention includes the negative electrode for a nonaqueous electrolyte power storage element according to one aspect of the present invention. According to any one of the aspects of the present invention, it is possible to provide a negative electrode for a nonaqueous electrolyte power storage element, which contains a substance alloyed with lithium element and a solid electrolyte and can improve the first coulombic efficiency of the nonaqueous electrolyte power stor