Polymer electrolyte and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-10700379-B2
Application number	US-201716080094-A
Country	US
Kind code	B2
Filing date	Sep 1, 2017
Priority date	Sep 2, 2016
Publication date	Jun 30, 2020
Grant date	Jun 30, 2020

Abstract

The present invention relates to a polymer electrolyte, which includes a lithium salt and a copolymer including a fluorine-substituted or unsubstituted polyalkylene ether repeating unit, and a lithium secondary battery including the same.

First claim

The invention claimed is:

1. A polymer electrolyte comprising:
a lithium salt; and
a copolymer represented by Formula 1b or 1c:

wherein, in Formula 1b and 1c,
each of m, n, and o is the number of repeating units,
m is an integer of 1 to 10,
n is an integer of 1 to 10, and
o is an integer of 1 to 500.

2. A polymer electrolyte, comprising:
a lithium salt; and
a copolymer represented by Formula 2:

wherein, in Formula 2,
R′ 1 and R′ 2 are each independently a fluorine-substituted or unsubstituted alkylene group having 1 to 4 carbon atoms,
R 3 is hydrogen, or an alkyl group having 1 to 6 carbon atoms,
R 4 is an alkylene group having 1 to 6 carbon atoms,
R 5 is an alkylene group having 1 to 5 carbon atoms, or —CO—NH—R 6 —NH—CO—O—,
R 6 is an aliphatic, alicyclic, or aromatic hydrocarbon group,
each of m1, n1, and o1 is the number of repeating units,
m1 is an integer of 1 to 10,
n1 is an integer of 1 to 10, and
o1 is an integer of 1 to 500.

3. The polymer electrolyte of claim 2 , wherein a weight ratio of the copolymer represented by Formula 1 to the lithium salt is in a range of 7:3 to 9.5:0.5.

4. The polymer electrolyte of claim 2 , wherein the aliphatic hydrocarbon group comprises an alkylene group having 1 to 20 carbon atoms; an alkylene group having 1 to 20 carbon atoms which contains an isocyanate group (NCO); an alkoxylene group having 1 to 20 carbon atoms; an alkenylene group having 2 to 20 carbon atoms; or an alkynylene group having 2 to 20 carbon atoms,
the alicyclic hydrocarbon group comprises a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms; a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms which contains an isocyanate group (NCO); a cycloalkenylene group having 4 to 20 carbon atoms; or a heterocycloalkylene group having 2 to 20 carbon atoms, and
the aromatic hydrocarbon group comprises a substituted or unsubstituted arylene group having 6 to 20 carbon atoms; or a heteroarylene group having 2 to 20 carbon atoms.

5. The polymer electrolyte of claim 2 , wherein the copolymer represented by Formula 2 comprises at least one selected from the group consisting of copolymers represented by Formulae 2a to 2c:

wherein, in Formula 2a,
each of m2, n2, and o2 is the number of repeating units,
m2 is an integer of 1 to 10,
n2 is an integer of 1 to 10, and
o2 is an integer of 1 to 500,

wherein, in Formula 2b,
each of m3, n3, and o3 is the number of repeating units,
m3 is an integer of 1 to 10,
n3 is an integer of 1 to 10, and
o3 is an integer of 1 to 500,

wherein, in Formula 2c,
each of m4, n4, and o4 is the number of repeating units,
m4 is an integer of 1 to 10,
n4 is an integer of 1 to 10, and
o4 is an integer of 1 to 500.

6. The polymer electrolyte of claim 2 , wherein the copolymer represented by Formula 2 has a weight-average molecular weight (Mw) of 200 g/mol to 100,000 g/mol.

7. The polymer electrolyte of claim 2 , further comprising a ceramic electrolyte.

8. The polymer electrolyte of claim 7 , wherein the ceramic electrolyte comprises a single material selected from the group consisting of a phosphate-based electrolyte selected from the group consisting of lithium phosphate, lithium titanium phosphate, lithium aluminum titanium phosphate, and lithium aluminum germanium phosphate; a sulfide-based electrolyte selected from the group consisting of SiS 2 (Li x Si y S z )-based glass, P 2 S 5 (Li x P y S z )-based glass, lithium germanium thiophosphate, and lithium phosphorus sulfide-based glass; lithium lanthanum titanate; lithium nitride; lithium lanthanum zirconate; and tantalum pentoxide, or a mixture of two or more thereof.

9. The polymer electrolyte of claim 2 , further comprising inorganic particles.

10. The polymer electrolyte of claim 9 , wherein the inorganic particles comprise a single material selected from the group consisting of Al 2 O 3 , BaTiO 3 , SnO 2 , CeO 2 , SiO 2 , TiO 2 , Li 3 PO 4 , NiO, ZnO, MgO, Mg(OH) 2 , CaO, ZrO 2 , Y 2 O 3 , Pb(Zr,Ti)O 3 , Pb 1-x La x Zr 1-y Ti y O 3 (where, 0<x<1 and 0<y<1), PB(Mg 3 Nb 2/3 )O 3 —PbTiO 3 , and hafnia, or a mixture of two or more thereof.

11. The polymer electrolyte of claim 2 , further comprising a plasticizer.

12. The polymer electrolyte of claim 11 , wherein the plasticizer comprises at least one compound of a carbonate-based compound, a lactone-based compound, an alkyl ether-based compound, an alkyl acetate-based compound, and an alkyl propionate-based compound.

13. 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 2 .

14. The lithium secondary battery of claim 13 , further selectively comprising a porous olefin-based separator between the positive electrode and the negative electrode.

Assignees

• Lg Chemical Ltd

Inventors

• Ahn Kyoung Ho
• Park Sol Ji
• Lee Jung Hoon
• Lee Chul Haeng

Classifications

• H01M50/417

  Polyolefins · CPC title

• H01M10/0567

  characterised by the additives · CPC title

• H01M10/056

  characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes · CPC title

• H01M2300/0091

  in the form of mixtures · CPC title

• H01M50/491

  Porosity · CPC title