Lithium secondary battery and production method therefor

Patent metadata

Field	Value
Publication number	US-10014555-B2
Application number	US-201314421523-A
Country	US
Kind code	B2
Filing date	Jul 31, 2013
Priority date	Aug 16, 2012
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

An embodiment of the present invention relates to a lithium secondary battery comprising a nonaqueous electrolytic solution comprising a phosphate compound represented by the following general formula (1): O═P(O—R 1 )(O—R 2 )(O—R 3 ) (1), wherein R 1 , R 2 , and R 3 are each alkyl group or the like or a group comprising an ether bond represented by —R 4 —O—R 5 (R 4 represents alkylene group, and R 5 represents alkyl group), and at least one of R 1 , R 2 , and R 3 is a group comprising an ether bond, and at least one of R 1 , R 2 , and R 3 contains fluorine, and a positive electrode active material having a charge and discharge region of 4.5 V or more versus lithium.

First claim

The invention claimed is:

1. A lithium secondary battery comprising a positive electrode comprising a positive electrode active material and a nonaqueous electrolytic solution, wherein
the nonaqueous electrolytic solution comprises a phosphate compound represented by the following general formula (1):
O═P(O—R 1 )(O—R 2 )(O—R 3 )  (1)

wherein among R 1 , R 2 , and R 3 , two are fluorine-containing alkyl groups, and the other is a group comprising an ether bond represented by —R 4 —O—R 5 in which R 4 represents alkylene group and R 5 represents a fluorine-containing alkyl group, and R 1 to R 5 may each independently have a substituent, and
the positive electrode active material has a charge and discharge region of 4.5 V or more versus lithium.

2. The lithium secondary battery according to claim 1 , wherein numbers of carbon atoms of R 1 , R 2 , and R 3 in the general formula (1) are each independently 1 or more and 6 or less.

3. The lithium secondary battery according to claim 1 , wherein a proportion of fluorine atoms in a total number of hydrogen atoms and fluorine atoms included in R 1 , R 2 , and R 3 in the general formula (1) is 30% or more.

4. The lithium secondary battery according to claim 1 , wherein the positive electrode active material comprises a lithium metal composite oxide represented by the following formula (2), (3), (4), or (5):
Li a (M x Mn 2-x-y Y y )(O 4-w Z w )  (2)

wherein 0.4<x<1.1, 0≤y, x+y<2, 0≤a≤1.2, and 0≤w≤1; M is at least one selected from the group consisting of Co, Ni, Fe, Cr, and Cu; Y is at least one selected from the group consisting of Li, B, Na, Al, Mg, Ti, Si, K, and Ca; and Z is at least one selected from the group consisting of F and Cl,
LiMPO 4   (3)

wherein M is at least one of Co and Ni,
Li(M 1-z Mn z )O 2   (4)

wherein 0.7≥z≥0.33, and M is at least one of Li, Co, and Ni,
Li(Li x M 1-x-z Mn 7 )O 2   (5)

wherein 0.3>x≥0.1, 0.7≥z≥0.33, and M is at least one of Co, Fe, and Ni.

5. The lithium secondary battery according to claim 1 , wherein the phosphate compound represented by the general formula (1) comprises at least one selected from the group consisting of:
O═P(O—CH 2 CF 3 ) 2 (O—C 2 H 4 —O—CH 2 CF 3 );

O═P(O—CH 2 CF 3 ) 2 (O—C 2 H 4 —O—CF 3 );

O═P(O—CH 2 CF 3 ) 2 (O—C 2 H 4 —O—CH 2 CH 2 F);

O═P(O—CH 2 C 3 F 7 ) 2 (O—C 2 H 4 —O—CH 2 C 3 F 7 ); and

O═P(O—CH 2 CF 3 ) 2 (O—CH 2 CF 2 —O—CF 3 ).

6. The lithium secondary battery according to claim 5 , wherein the phosphate compound represented by the general formula (1) comprises at least one selected from the group consisting of:
O═P(O—CH 2 CF 3 ) 2 (O—C 2 H 4 —O—CH 2 CF 3 ),

O═P(O—CH 2 CF 3 ) 2 (O—CH 2 CF 2 —O—CF 3 ), and

O═P(O—CH 2 CF 3 ) 2 (O—C 2 H 4 —O—CH 2 CH 2 F).

7. The lithium secondary battery according to claim 6 , wherein the phosphate compound represented by the general formula (1) comprises at least one selected from the group consisting of:
O═P(O—CH 2 CF 3 ) 2 (O—C 2 H 4 —O—CH 2 CF 3 ) and

O═P(O—CH 2 CF 3 ) 2 (O—CH 2 CF 2 —O—CF 3 ).

8. The lithium secondary battery according to claim 1 , wherein the nonaqueous electrolytic solution further comprises 50 vol % or more of a fluorine-containing phosphate other than the phosphate compound represented by the general formula (1).

9. The lithium secondary battery according to claim 8 , wherein the phosphate compound represented by the general formula (1) is included in the nonaqueous electrolytic solution in the range of 0.01% by mass or more and 1% by mass or less.

10. The lithium secondary battery according to claim 1 , wherein the phosphate compound represented by the general formula (1) is included in the nonaqueous electrolytic solution in the range of 0.01% by mass or more and 1% by mass or less.

11. The lithium secondary battery according to claim 1 , wherein the phosphate compound represented by the general formula (1) is included in the nonaqueous electrolytic solution in the range of 0.1% by mass or more and 0.5% by mass or less.

12. The lithium secondary battery according to claim 1 , wherein the nonaqueous electrolytic solution further comprises tris(2,2,2-trifluoroethyl) phosphate.

13. A method for manufacturing a lithium secondary battery, comprising a step of enclosing in a package a positive electrode having a positive electrode active material having a charge and discharge region of 4.5 V or more versus lithium, a negative electrode, and a nonaqueous electrolytic solution comprising a phosphate compound represented by the following general formula (1):
O═P(O−R 1 )(O—R 2 )(O—R 3 )  (1)

wherein among R 1 , R 2 , and R 3 , two are fluorine-containing alkyl groups, and the other is a group comprising an ether bond represented by —R 4 —O—R 5 in which R 4 represents alkylene group and R 5 represents a fluorine-containing alkyl group, and R 1 to R 5 may each independently have a substituent.

Assignees

• Nec Corp

Inventors

• Noguchi Takehiro
• Sasaki Hideaki
• Takahashi Makiko
• Katou Yuukou

Classifications

• Y10T29/49108

  Electric battery cell making · CPC title

• H01M10/0525

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

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title