Polymer electrolyte for secondary battery and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-11114692-B2
Application number	US-201816468589-A
Country	US
Kind code	B2
Filing date	Jul 3, 2018
Priority date	Jul 6, 2017
Publication date	Sep 7, 2021
Grant date	Sep 7, 2021

Abstract

The present invention relates to a polymer electrolyte for a secondary battery and a lithium secondary battery comprising the same, and particularly, to a polymer electrolyte for a secondary battery, in which mechanical properties, ionic conductivity, and electrical conductivity are improved by comprising a polymer and an electron-acceptor having at least one double bond, as a dopant, and a lithium secondary battery in which electrochemical stability at high temperature and high voltage is enhanced by comprising the polymer electrolyte.

First claim

The invention claimed is:

1. A polymer electrolyte for a secondary battery, the polymer electrolyte comprising:
a polymer represented by Formula 1 or Formula 2; and
an electron-acceptor having at least one double bond, as a dopant:

wherein R and R 5 are each independently carbon (C) or sulfur (S),
R 1 is

wherein R 9 is —C(CF 3 ) 2 —,
R 2 and R 7 are

R 3 is —S(CF 2 ) 2 SO 3 − Li + ,
R 4 is

wherein R 10 is —C(CF 3 ) 2 —,
R 6 is

wherein R 9 is —C(CF 3 ) 2 —,
R 8 is

o and o1 are 1 or 2,
p, p1, q, q1, r, and s are 0 or 1,
a ratio of n:m is in a range of 95:5 to 5:95 as a molar ratio, and
a ratio of n′:m′ is in a range of 95:5 to 5:95 as a molar ratio.

2. The polymer electrolyte for a secondary battery of claim 1 , wherein, in Formula 1, the ratio of n:m is in a range of 40:60 to 60:40 as a molar ratio, and
in Formula 2, the ratio of n′:m′ is in a range of 40:60 to 60:40 as a molar ratio.

3. The polymer electrolyte for a secondary battery of claim 1 , wherein the polymer represented by Formula 1 or Formula 2 has a weight-average molecular weight (Mw) of 5,000 g/mol to 1,500,000 g/mol.

4. The polymer electrolyte for a secondary battery of claim 1 , wherein the polymer represented by Formula 1 comprises at least one selected from the group consisting of compounds represented by Formulae 1a to 1c:

wherein, in Formulae 1a to 1c,
a ratio of n2:m2 is in a range of 95:5 to 5:95 as a molar ratio,
a ratio of n3:m3 is in a range of 95:5 to 5:95 as a molar ratio, and
a ratio of n4:m4 is in a range of 95:5 to 5:95 as a molar ratio.

5. The polymer electrolyte for a secondary battery of claim 1 , wherein the electron-acceptor comprises at least one selected from the group consisting of Formulae 3 to 7:

6. The polymer electrolyte for a secondary battery of claim 1 , wherein a molar ratio of the polymer:the electron-acceptor is in a range of 1:0.01 to 1:500.

7. The polymer electrolyte for a secondary battery of claim 1 , further comprising a lithium salt.

8. The polymer electrolyte for a secondary battery of claim 7 , wherein the lithium salt comprises Li + as a cation, and
comprises at least one selected from the group consisting of F − , Cl − , Br − , I − , NO 3 − , N(CN) 2 − , BF 4 − , ClO 4 − , AlO 4 − , AlCl 4 − , PF 6 − , SbF 6 − , AsF 6 − , BF 2 C 2 O 4 − , B(C 2 O 4 ) 2 − , (CF 3 ) 2 PF 4 − , (CF 3 ) 3 PF 3 − , (CF 3 ) 4 PF 2 − , (CF 3 ) 5 PF − , (CF 3 ) 6 P − , CF 3 SO 3 − , C 4 F 9 SO 3 − , CF 3 CF 2 SO 3 − , (CF 3 SO 2 ) 2 N − , (FSO 2 ) 2 N − , CF 3 CF 2 (CF 3 ) 2 CO − , (CF 3 SO 2 ) 2 N—, (SF 5 ) 3 C − , (CF 3 SO 2 ) 3 C − , CF 3 (CF 2 ) 7 SO 3 − , CF 3 CO 2 − , CH 3 CO 2 − , SCN − , and (CF 3 CF 2 SO 2 ) 2 N − as an anion.

9. The polymer electrolyte for a secondary battery of claim 7 , wherein the lithium salt is comprised in a concentration of 0.5 M to 5 M in the polymer electrolyte for a secondary battery.

10. The polymer electrolyte for a secondary battery of claim 1 , wherein the polymer electrolyte is a free-standing solid polymer electrolyte.

11. The polymer electrolyte for a secondary battery of claim 1 , further comprising an ionic liquid.

12. The polymer electrolyte for a secondary battery of claim 11 , wherein the ionic liquid comprises at least one selected from the group consisting of diethylmethylammonium trifluoromethanesulfonate, dimethylpropylammonium trifluoromethanesulfonate, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, 1-ethyl-3-methylimidazolium-bi s(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide, and methyl propylpiperidinium trifluoromethanesulfonylimide.

13. The polymer electrolyte for a secondary battery of claim 11 , wherein the ionic liquid is comprised in an amount of 0.01 wt % to 50 wt % based on a total weight of the polymer electrolyte.

14. The polymer electrolyte for a secondary battery of claim 11 , wherein the polymer electrolyte is a solid polymer-liquid hybrid electrolyte.

15. A lithium secondary battery comprising:
a positive electrode;
a negative electrode; and
a polymer electrolyte formed on at least one surface of the positive electrode and the negative electrode,
wherein the polymer electrolyte comprises the polymer electrolyte for a secondary battery of claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Park Sol Ji
• Ahn Kyoung Ho
• Kim Young Jea
• Jang Yong Jin
• Han Joong Jin
• Lee Chul Haeng

Classifications

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title

• H01M2300/0025

  Organic electrolyte · CPC title

• H01M2300/0082

  Organic polymers · CPC title

• H01M10/0525 Primary

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

• H01M2300/0045

  Room temperature molten salts comprising at least one organic ion · CPC title