Lithium ion secondary battery

Patent metadata

Field	Value
Publication number	US-9692085-B2
Application number	US-201214356710-A
Country	US
Kind code	B2
Filing date	Oct 26, 2012
Priority date	Nov 10, 2011
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

It is an object of this exemplary embodiment to provide a lithium ion secondary battery using a positive electrode active material having an operating potential of 4.5 V or more, the lithium ion secondary battery having excellent high temperature cycle characteristics. This exemplary embodiment is a lithium ion secondary battery comprising a positive electrode and a negative electrode capable of intercalating and deintercalating lithium, a separator between the positive electrode and the negative electrode, and an electrolytic solution containing a nonaqueous electrolytic solvent, wherein the positive electrode comprises a positive electrode active material operating at a potential of 4.5 V or more versus lithium, the separator comprises cellulose, a cellulose derivative, or a glass fiber, and the nonaqueous electrolytic solvent comprises a fluorinated solvent.

First claim

The invention claimed is:

1. A lithium ion secondary battery comprising a positive electrode and a negative electrode which are capable of intercalating and deintercalating lithium, a separator between the positive electrode and the negative electrode, and an electrolytic solution containing a nonaqueous electrolytic solvent, wherein
the positive electrode comprises a positive electrode active material operating at a potential of 4.5 V or more versus lithium,
the separator comprises cellulose, or a cellulose derivative,
the nonaqueous electrolytic solvent comprises a fluorinated solvent in an amount ranging from 5 to 80% by volume, wherein said fluorinated solvent comprises a fluorinated ether represented by the following formula (1-1);
R 101 —O—R 102   (1-1)

wherein R 101 and R 102 each independently represent an alkyl group having 1 to 12 carbon atoms or a fluorine-substituted alkyl group having 1 to 6 carbon atoms, and at least one of R 101 and R 102 is the fluorine-substituted alkyl group,
the porosity of the separator ranges from at least 50% through 95%, and
the positive electrode active material comprises lithium manganese complex oxide represented by the following formula (A),
Li a (M x Mn 2-x-y Y y )(O 4-w Z w )  (A)

wherein 0.4≦x≦1.2, 0≦y<0.3, x+y<2, 0≦a≦1.2, and 0≦w≦1 are satisfied; M is at least one selected from Co, Ni, Fe, Cr, and Cu; Y is at least one selected from Li, B, Na, Mg, Al, Ti, Si, K, and Ca; and Z is at least one selected from F and Cl.

2. The lithium ion secondary battery according to claim 1 , wherein the separator is a cellulose-containing separator.

3. The lithium ion secondary battery according to claim 1 , wherein the separator is a cellulose derivative-containing separator.

4. The lithium ion secondary battery according to claim 1 , wherein the nonaqueous electrolytic solvent further comprises a carbonate compound in an amount ranging from 10 to 90% by volume.

5. The lithium ion secondary battery according to claim 4 , wherein the nonaqueous electrolytic solvent further comprises a carbonate compound,
a content of the fluorinated solvent in the nonaqueous electrolytic solvent is 10 to 50% by volume, and
a content of the carbonate compound in the nonaqueous electrolytic solvent is 50 to 90% by volume.

Assignees

• Nec Corp

Inventors

• Uehara Makiko
• Noguchi Takehiro

Classifications

• H01M50/491

  Porosity · CPC title

• H01M50/437

  Glass · CPC title

• H01M2/1626

  Electricity · mapped topic

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M2/1613

  Electricity · mapped topic