Carbon conductive additives for lithium ion battery

Patent metadata

Field	Value
Publication number	US-11349152-B2
Application number	US-201716631540-A
Country	US
Kind code	B2
Filing date	Jul 20, 2017
Priority date	Jul 20, 2017
Publication date	May 31, 2022
Grant date	May 31, 2022

Abstract

The invention provides a lithium ion battery, including an anode, a cathode and an electrolytic solution including imide anion based lithium salt and LiPO2F2. The cathode includes a cathode active material particle and a carbon conductive additive forming an island-bridge structure on the surface of the cathode active material particle. The carbon conductive additive includes graphenes partially covered with the surface of the cathode active material particle to form an island structure, carbon blacks attached on the surface of the graphene and carbon nanotubes connecting between graphenes as a bridge structure.

First claim

The invention claimed is:

1. A cathode comprising a cathode active material particle and a carbon conductive additive forming an island-bridge structure on the surface of the cathode active material particle,
wherein the carbon conductive additive comprises graphenes partially covered with the surface of the cathode active material particle to form an island structure, carbon blacks attached on the surface of the graphene and carbon nanotubes connecting between graphenes as a bridge structure, and
wherein a weight ratio of the graphenes to the carbon nanotubes is 5/1 to 1/5, a total amount of the graphenes and the carbon nanotubes is 0.5 to 10 parts by weight per 100 parts by weight of the cathode active material particle, and an amount of the carbon black is 5 to 10 parts by weight per 100 parts by weight of the cathode active material particle.

2. The cathode according to claim 1 , wherein the graphene is a monolayer graphene and/or multi-layered graphene with up to 30 layers.

3. The cathode according to claim 1 , wherein the length of the carbon nanotube is 5 nm to 50 μm; and the diameter of the carbon nanotube is 1.2 nm to 100 nm.

4. The cathode according to claim 1 , wherein the weight ratio of graphene to the carbon nanotubes is from 5/1 to 1/1.

5. The cathode according to claim 1 , wherein the total amount of the graphenes and the carbon nanotubes is 1 to 7 parts by weight per 100 parts by weight of the cathode active particle.

6. A lithium ion battery, comprising the cathode according to claim 1 , and an electrolytic solution comprising an ionic liquid of an imide anion based lithium salt and LiPO 2 F 2 .

7. The lithium ion battery according to claim 6 , wherein the electrolytic solution comprises a composite of the ionic liquid and a lithium salt other than the ionic liquid as an electrolyte and the mole ratio of the ionic liquid to the lithium salt is from 1/9 to 9/1.

8. The lithium ion battery according to claim 6 , wherein the total concentration of the electrolyte in the electrolytic solution is in the range of 0.1 to 3 moles/L.

9. The lithium ion battery according to claim 6 , wherein the electrolytic solution comprises ethylene carbonate (EC), dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC) as solvents, with the volume ratio of EC/DMC/EMC being x:y:100−x−y, where x is 15 to 50% by volume, y is 20 to 60% by volume and x+y is less than 100% by volume.

10. The lithium ion battery according to claim 6 , wherein an amount of LiPO 2 F 2 is 0.005 to 7 wt % in the electrolytic solution.

11. A lithium ion battery, comprising the cathode according to claim 2 , and an electrolytic solution comprising an ionic liquid of an imide anion based lithium salt and LiPO 2 F 2 .

12. The lithium ion battery according to claim 11 , wherein the electrolytic solution comprises a composite of the ionic liquid and a lithium salt other than the ionic liquid as an electrolyte and the mole ratio of the ionic liquid to the lithium salt is from 1/9 to 9/1.

13. A lithium ion battery, comprising the cathode according to claim 3 , and an electrolytic solution comprising an ionic liquid of an imide anion based lithium salt and LiPO 2 F 2 .

14. The lithium ion battery according to claim 13 , wherein the electrolytic solution comprises a composite of the ionic liquid and a lithium salt other than the ionic liquid as an electrolyte and the mole ratio of the ionic liquid to the lithium salt is from 1/9 to 9/1.

15. A lithium ion battery, comprising the cathode according to claim 4 , and an electrolytic solution comprising an ionic liquid of an imide anion based lithium salt and LiPO 2 F 2 .

16. The lithium ion battery according to claim 15 , wherein the electrolytic solution comprises a composite of the ionic liquid and a lithium salt other than the ionic liquid as an electrolyte and the mole ratio of the ionic liquid to the lithium salt is from 1/9 to 9/1.

17. A lithium ion battery, comprising the cathode according to claim 5 , and an electrolytic solution comprising an ionic liquid of an imide anion based lithium salt and LiPO 2 F 2 .

18. The lithium ion battery according to claim 17 , wherein the electrolytic solution comprises a composite of the ionic liquid and a lithium salt other than the ionic liquid as an electrolyte and the mole ratio of the ionic liquid to the lithium salt is from 1/9 to 9/1.

Assignees

• Nec Corp

Inventors

• Cheng Qian
• Maeda Katsumi
• Tamura Noriyuki
• Shiba Mika

Classifications

• H01M10/0567 Primary

  characterised by the additives · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/525

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M10/0568

  characterised by the solutes · CPC title