Electrolytic solution, electrochemical device, lithium ion secondary battery, and module

Patent metadata

Field	Value
Publication number	US-9570778-B2
Application number	US-201314394301-A
Country	US
Kind code	B2
Filing date	Apr 12, 2013
Priority date	Apr 17, 2012
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

The present invention aims to provide an electrolyte solution for forming, for example, a secondary battery having excellent oxidation resistance and high-temperature storage characteristics; an electrochemical device such as a lithium-ion secondary battery that contains the electrolyte solution; and a module that contains the electrochemical device. The present invention provides an electrolyte solution containing a solvent and an electrolyte salt, wherein the solvent contains a fluorine-containing compound (A) represented by formula (1) shown below in an amount of 0.01 to 20% by mass, and a fluorine-containing compound (B) represented by formula (2) shown below in an amount of 10 to 80% by mass:

Rf 1 OCOOR  (1)

wherein Rf 1 is a C1-C4 fluorine-containing alkyl group, and R is a C1-C4 non-fluorinated alkyl group, and

Rf 2 OCOORf 3   (2)

wherein Rf 2 and Rf 3 are the same or different, and each is a C1-C4 fluorine-containing alkyl group.

First claim

The invention claimed is:

1. An electrolyte solution comprising:
a solvent; and
an electrolyte salt,
the solvent containing a fluorine-containing compound (A) represented by formula (1) shown below in an amount of 0.01 to 20% by mass and a fluorine-containing compound (B) represented by formula (2) shown below in an amount of 20 to 80% by mass:
Rf 1 OCOOR  (1)

wherein Rf 1 is a C1-C4 fluorine-containing alkyl group, and R is a C1-C4 non-fluorinated alkyl group, and
Rf 2 OCOORf 3   (2)

wherein Rf 2 and Rf 3 are the same or different, and each is a C1-C4 fluorine-containing alkyl group,
wherein the fluorine-containing compound (A) is at least one compound selected from the group consisting of CF 3 CH 2 OCOOCH 3 , CF 3 CH 2 OCOOCH 2 CH 3 , CF 3 CF 2 CH 2 OCOOCH 3 , and CF 3 CF 2 CH 2 OCOOCH 2 CH 3 ; and the fluorine-containing compound(B) is at least one compound selected from the group consisting of CF 3 CH 2 OCOOCH 2 CF 3 , CF 2 HCF 2 CH 2 OCOOCH 2 CF 2 CF 2 H, and (CF 3 ) 2 CHOCOOCH(CF 3 ) 2 .

2. The electrolyte solution according to claim 1 ,
wherein the fluorine-containing compound (A) is at least one compound selected from the group consisting of CF 3 CH 2 OCOOCH 3 and CF 3 CH 2 OCOOC 2 H 5 ; and the fluorine-containing compound(B) is CF 3 CH 2 OCOOCH 2 CF 3 .

3. The electrolyte solution according to claim 1 ,
wherein the solvent further comprises at least one selected from the group consisting of a non-fluorinated saturated cyclic carbonate, a fluorinated saturated cyclic carbonate, and a non-fluorinated chain carbonate.

4. The electrolyte solution according to claim 3 ,
wherein the non-fluorinated saturated cyclic carbonate is at least one compound selected from the group consisting of ethylene carbonate, propylene carbonate, and butylene carbonate.

5. The electrolyte solution according to claim 3 ,
wherein the non-fluorinated chain carbonate is at least one compound selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl butyl carbonate, ethyl propyl carbonate, and ethyl butyl carbonate.

6. The electrolyte solution according to claim 1 ,
wherein a mass ratio A/B of the fluorine-containing compound (A) to the fluorine-containing compound (B) is less than 1.

7. The electrolyte solution according to claim 1 ,
wherein the electrolyte salt is at least one lithium salt selected from the group consisting of LiPF 6 , LiBF 4 , LiSO 3 CF 3 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, and a salt represented by a formula: LiPF a (C n F 2n+1 ) 6-a wherein a is an integer of 0 to 5 and n is an integer of 1 to 6.

8. The electrolyte solution according to claim 1 ,
wherein the electrolyte solution comprises 0.5 to 70 ppm of HF.

9. The electrolyte solution according to claim 1 ,
wherein the electrolyte solution further comprises at least one compound selected from the group consisting of an unsaturated cyclic carbonate, a fluorinated saturated cyclic carbonate, and a cyclic sulfonic acid compound, in an amount of 0.1 to 10% by mass.

10. An electrochemical device comprising the electrolyte solution as defined in claim 1 .

11. A lithium-ion secondary battery comprising the electrolyte solution as defined in claim 1 .

12. A module comprising the electrochemical device as defined in claim 10 .

Assignees

• Daikin Ind Ltd

Inventors

• Yamazaki Shigeaki
• Sakata Hideo
• Taeda Mayuko
• Koh Meiten
• Nakazono Aoi
• Kagawa Michiru
• Yamauchi Akiyoshi

Classifications

• H01M10/0525 Primary

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M10/0568

  characterised by the solutes · CPC title

• H01M2300/0034

  Fluorinated solvents · CPC title

• H01M10/0567

  characterised by the additives · CPC title