Electrode, negative electrode active material, negative electrode, secondary battery, moving vehicle, electronic device, method for fabricating negative electrode active material, and method for fabricating negative electrode

Patent metadata

Field	Value
Publication number	US-2025246612-A1
Application number	US-202519182887-A
Country	US
Kind code	A1
Filing date	Apr 18, 2025
Priority date	Aug 7, 2020
Publication date	Jul 31, 2025
Grant date	—

Abstract

A negative electrode with little deterioration is provided. A novel negative electrode is provided. A power storage device with little deterioration is provided. A novel power storage device is provided. The electrode contains silicon, graphite, and a graphene compound. A silicon particle with a particle diameter of less than or equal to 1 μm is attached to a graphite particle with a particle diameter 10 times or more that of the silicon particle. The graphene compound is in contact with the graphite particle so as to cover the silicon particle.

First claim

1 . A lithium-ion secondary battery comprising a positive electrode, a negative electrode, an electrolyte solution, and a separator,
wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide, wherein a fluorine exists in a part of oxygen sites of the lithium cobalt oxide, wherein the positive electrode active material comprises titanium, magnesium, and oxygen at a surface portion of the positive electrode active material, wherein the positive electrode active material comprises a pseudo-spinel crystal structure due to an extraction of lithium ion in a charged state, wherein the negative electrode comprises a first negative electrode active material comprising silicon and a second negative electrode active material comprising graphite, wherein the negative electrode further comprises graphene or graphene compound, wherein the first negative electrode active material is in contact with the second negative electrode active material, wherein the graphene or the graphene compound is in contact with the first negative electrode active material and the second negative electrode active material, and wherein, in a charge and discharge state, when the lithium-ion secondary battery is charged, the lithium ion extracted from the positive electrode active material of the positive electrode is inserted into the first negative electrode active material, and when the lithium-ion secondary battery is discharged, the lithium ion is inserted into the positive electrode active material of the positive electrode.

2 . A lithium-ion secondary battery comprising a positive electrode, a negative electrode, an electrolyte solution, and a separator,
wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide, wherein a fluorine exists in a part of oxygen sites of the lithium cobalt oxide, wherein the positive electrode active material comprises titanium, magnesium, and oxygen at a surface portion of the positive electrode active material, wherein the positive electrode active material comprises a pseudo-spinel crystal structure due to an extraction of lithium ion in a charged state, wherein the negative electrode comprises a first negative electrode active material comprising a silicon compound and a second negative electrode active material comprising a graphite, wherein the negative electrode further comprises graphene or graphene compound, wherein the first negative electrode active material is in contact with the second negative electrode active material, wherein the graphene or the graphene compound is in contact with the first negative electrode active material and the second negative electrode active material, and wherein, in a charge and discharge state, when the lithium-ion secondary battery is charged, the lithium ion extracted from the positive electrode active material of the positive electrode is inserted into the silicon compound, and when the lithium-ion secondary battery is discharged, the lithium ion is inserted into the positive electrode active material of the positive electrode.

3 . A lithium-ion secondary battery comprising a positive electrode, a negative electrode, an electrolyte solution, and a separator,
wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide, wherein a fluorine exists in a part of oxygen sites of the lithium cobalt oxide, wherein the positive electrode active material comprises titanium, magnesium, and oxygen at a surface portion of the positive electrode active material, wherein the positive electrode active material comprises a pseudo-spinel crystal structure due to an extraction of lithium ion in a charged state, wherein the negative electrode comprises a first negative electrode active material comprising silicon and a second negative electrode active material with a particle diameter of larger than the first active material, wherein the negative electrode further comprises graphene or graphene compound, wherein the first negative electrode active material is in contact with the second negative electrode active material, wherein the graphene or the graphene compound is in contact with the first negative electrode active material and the second negative electrode active material, and wherein, in a charge and discharge state, when the lithium-ion secondary battery is charged, the lithium ion extracted from the positive electrode active material of the positive electrode is inserted into the first negative electrode active material, and when the lithium-ion secondary battery is discharged, the lithium ion is inserted into the positive electrode active material of the positive electrode.

4 . A lithium-ion secondary battery comprising a positive electrode, a negative electrode, an electrolyte solution, and a separator,
wherein the positive electrode comprises a positive electrode active material comprising lithium cobalt oxide, wherein a fluorine exists in a part of oxygen sites of the lithium cobalt oxide, wherein the positive electrode active material comprises titanium, magnesium, and oxygen at a surface portion of the positive electrode active material, wherein the positive electrode active material comprises a pseudo-spinel crystal structure due to an extraction of lithium ion in a charged state, wherein the negative electrode comprises a first negative electrode active material comprising a silicon compound and a second negative electrode active material with a particle diameter of larger than the first active material, wherein the negative electrode further comprises graphene or graphene compound, wherein the first negative electrode active material is in contact with the second negative electrode active material, wherein the graphene or the graphene compound is in contact with the first negative electrode active material and the second negative electrode active material, and wherein, in a charge and discharge state, when the lithium-ion secondary battery is charged, the lithium ion extracted from the positive electrode active material of the positive electrode is inserted into the silicon compound, and when the lithium-ion secondary battery is discharged, the lithium ion is inserted into the positive electrode active material of the positive electrode.

5 . The lithium-ion secondary battery according to claim 1 ,
wherein the first negative electrode active material comprises amorphous silicon or polycrystalline silicon.

6 . The lithium-ion secondary battery according to claim 3 ,
wherein the first negative electrode active material comprises amorphous silicon or polycrystalline silicon.

7 . The lithium-ion secondary battery according to claim 2 ,
wherein the silicon compound is SiO x , and wherein x is less than 2.

8 . The lithium-ion secondary battery according to claim 4 ,
wherein the silicon compound is SiO x , and wherein x is less than 2.

9 . The lithium-ion secondary battery according to claim 2 ,
wherein the silicon compound comprises Li 2 SiO 3 or Li 4 SiO 4 .

10 . The lithium-ion secondary battery according to claim 4 ,
wherein the silicon compound comprises Li 2 SiO 3 or Li 4 SiO 4 .

11 . The lithium-ion secondary battery according to claim 1 ,
wherein the charged state is a state where the positive electrode active material is charged at voltages of 4.65 V to 4.7 V with reference to the potential of lithium metal.

12 . The lithium-ion secondary battery according to claim 1 ,
wherein the charged state is a state where the positive electrode active material is charged at voltages of 4.65 V to 4.7 V with reference to t

Assignees

• Semiconductor Energy Lab

Inventors

• Kuriki Kazutaka
• Nakao Taisuke
• Asada Yoshiharu
• Yoneda Yumiko

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/483

  for non-aqueous cells (H01M4/485 takes precedence) · CPC title