Composite material, electrode, electrode device, power storage device and method of manufacturing composite material

Patent metadata

Field	Value
Publication number	US-11532811-B2
Application number	US-202016814299-A
Country	US
Kind code	B2
Filing date	Mar 10, 2020
Priority date	Mar 12, 2019
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

A composite material includes vanadium lithium phosphate, and a conductive carbon. an amount of the conductive carbon is 2.5 mass % or more and 7.5 mass % or less.

First claim

What is claimed is:

1. A composite material, comprising:
vanadium lithium phosphate; and
a coating layer including conductive carbon and vanadium, wherein
the conductive carbon is present in the coating layer at 4.0 mass % or more and 7.5 mass %, and
the vanadium is present in the coating layer at 5 at % or less as measured by energy dispersive X-ray analysis.

2. The composite material as claimed in claim 1 , wherein a true density of the composite material is 2.90 g·cm −3 or more.

3. The composite material as claimed in claim 1 , wherein a crystallite size of the composite material is 55 nm or less.

4. The composite material as claimed in claim 1 , wherein
the vanadium lithium phosphate is expressed by a chemical formula Li 3 V 2 (PO 4 ) 3 or a general formula LixV 2 -yMy(PO 4 )z, wherein
x, y and z satisfy 0<x≤3, 0≤y<2, and 2≤z≤3, respectively, and
M is at least one selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, Sr, Zr, Nb, Y, Na, and W.

5. The composite material as claimed in claim 1 , wherein
the composite material is an additive for a power storage device.

6. An electrode containing the composite material as claimed in claim 1 .

7. An electrode device, comprising:
a positive electrode;
a negative stacked over the positive electrode while being electrically insulated from the positive electrode, wherein
the positive electrode is made of the electrode as claimed in claim 6 .

8. A power storage device, comprising:
a positive electrode;
a negative electrode electrically insulated from the positive electrode; and
an electrolyte, wherein
the positive electrode is made of the electrode as claimed in claim 6 .

9. A method of manufacturing a composite material containing an active material and a conductive carbon, comprising:
preparing a lithium phosphate aqueous solution;
adding a vanadium source and at least one of a conductive carbon and a conductive carbon precursor to the lithium phosphate aqueous solution;
stirring the vanadium source and the at least one of the conductive carbon and the conductive carbon precursor in the lithium phosphate aqueous solution;
milling a resulting object obtained by the stirring step, thereby obtaining a milled object;
pre-baking the milled object at a first temperature; and
baking the milled object at a second temperature higher than the first temperature, wherein
the pre-baking and the baking are performed in a same chamber to form a composite material that comprises vanadium lithium phosphate, and a coating layer that includes conductive carbon and vanadium,
the conductive carbon being present in the coating layer at 4.0 mass % or more and 7.5 mass %, and
the vanadium being present in the coating layer at 5 at % or less as measured by energy dispersive X-ray analysis.

10. The method as claimed in claim 9 , wherein
the first temperature in the pre-baking step is 100° C. or higher and 500° C. or lower.

11. The method as claimed in claim 9 , wherein
a temperature increasing rate of the pre-baking step is T/4° C.·h −1 or higher and 2T° C.·h −1 or lower when the first temperature is made T.

12. The method as claimed in claim 9 , further comprising:
drying the milled object obtained in the milling step, wherein
the baking step comprises baking the dried milled object in the drying step.

13. The method as claimed in claim 12 , wherein
a concentration of a solid matter of the milled object in the drying step is 15 mass % or more and 30 mass % or less.

14. The method as claimed in claim 9 , wherein
the solvent in the stirring step contains water as a principal component.

15. The method as claimed in claim 9 , wherein
the active material is lithium vanadium phosphate.

16. The method as claimed in claim 15 , wherein
the stirring step comprises stirring a source of lithium, a source of phosphate, a source of vanadium, a conductive carbon or a conductive carbon precursor in the solvent.

17. The method as claimed in claim 15 , wherein
the stirring step comprises adding a source of vanadium, and one of the conductive carbon and the conductive carbon precursor to an aqueous lithium phosphate solution, and then stirring the aqueous lithium phosphate solution.

18. A method of manufacturing a composite material containing an active material and a conductive carbon, comprising:
preparing a lithium phosphate aqueous solution;
adding a vanadium source and at least one of a conductive carbon and a conductive carbon precursor to the lithium phosphate aqueous solution;
stirring the vanadium source and the at least one of the conductive carbon and the conductive carbon precursor in the lithium phosphate aqueous solution;
milling a resulting object obtained by the stirring step, thereby obtaining a milled object;
pre-baking the milled object at a first temperature; and
baking the milled object at a second temperature higher than the first temperature, wherein
the pre-baking and the baking are performed in a same chamber to form a composite material that comprises vanadium lithium phosphate, and a coating layer that includes conductive carbon and vanadium,
the conductive carbon being present in the coating layer at 4.0 mass % or more and 7.5 mass %, and
the vanadium being present in the coating layer at 5 at % or less as measured by energy dispersive X-ray analysis.

19. The composite material as claimed in claim 1 , wherein
the composite material has a powder resistance of 100 Ωcm or less.

Assignees

• Kanno Yusuke
• Yanagita Hideo
• Nakajima Satoshi
• Suzuki Eiko
• Hirowatari Anna
• Ricoh Co Ltd

Inventors

• Kanno Yusuke
• Yanagita Hideo
• Nakajima Satoshi
• Suzuki Eiko
• Hirowatari Anna

Classifications

• H01M4/1397

  of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/366

  as layered products · CPC title

• H01M4/5825 Primary

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• C01P2006/40

  Electric properties · CPC title