Polymer electrolyte, method of preparing the polymer electrolyte, and lithium metal battery including the same

1. A polymer electrolyte comprising a polymerization product of:

a polymer comprising an unsaturated functional group at a terminal thereof and a fluoroalkylene chain, and

an ion-conductive polymer comprising an unsaturated functional group at a terminal thereof,

wherein the polymer having an unsaturated functional group at a terminal thereof and a fluoroalkylene chain is a compound represented by Formula 3:

wherein, in Formula 3,

L 1 and L 3 are each independently a bond or —C(═O)O—R—NH—, wherein R is a divalent, trivalent or tetravalent group and selected from a C1-C20 aliphatic hydrocarbon group, a C5-C40 cycloaliphatic group, a C5-C40 cycloaliphatic urethane group, a C6-C40 aryl group, and a C2-C40 heteroaryl group,

A 1 and A 2 are each independently a bond or a divalent, trivalent or tetravalent bonding group,

L 2 is a fluoropolyalkylene oxide chain or a perfluoropolyalkylene oxide chain,

R 1 and R 2 are each independently a hydrogen or a C1-C5 alkyl group, and

n and m are each independently an integer from 1 to 3;

wherein the ion-conductive polymer comprising an unsaturated functional group at a terminal thereof is a polymer represented by Formula 1 or Formula 2,

wherein, in Formula 1,

R 1 and R 2 are each independently a hydrogen or a C1-C5 alkyl group, and L is one selected from groups represented by Formula 1a,

wherein, in Formula 1a,

R 1 is a C1-C5 alkylene group,

R 2 and R 3 are each independently a C1-C5 alkyl group,

a is an integer from 1 to 10,

k is an integer from 1 to 10,

l is an integer from 1 to 10,

n is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom;

wherein, in Formula 2,

R 1 is a hydrogen or a C1-C5 alkyl group, and

L′ is one selected from groups represented by Formula 2a,

wherein, in Formula 2a,

a is an integer from 1 to 10,

R 1 is a C1-C5 alkylene group,

R 0 and R 2 to R 6 are each independently a C1-C10 alkyl group, a C6-C10 aryl group, or a C1-C10 heteroaryl group,

k is an integer from 1 to 10,

l is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom;

wherein the polymerization product is a compound represented by Formula 8 or a compound represented by Formula 9,

wherein, in Formula 8,

l is an integer from 1 to 10,

m is an integer from 1 to 10,

each n is an integer from 1 to 10,

R 1 and R are independently hydrogen or a C1-C5 alkyl group,

is a group represented by the following formula,

wherein, in the above formula,

L1 and L3 are each independently a bond or —C(═O)O—R—NH—, wherein R is a divalent, trivalent or tetravalent group, and selected from a C1-C20 aliphatic hydrocarbon group, a C5-C40 cycloaliphatic group, a C5-C40 cycloaliphatic urethane group, a C6-C40 aryl group, and a C2-C40 heteroaryl group,

A1 and A2 are each independently a bond or a divalent, trivalent or tetravalent bonding group,

L2 is a fluoropolyalkylene oxide chain or a perfluoropolyalkylene oxide chain,

is L, wherein L is one selected from groups represented by Formula 1a,

wherein, in Formula 1a,

R1 is a C1-05 alkylene group,

R2 and R3 are each independently a C1-C5 alkyl group,

a is an integer from 1 to 10,

k is an integer from 1 to 10,

l is an integer from 1 to 10,

n is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom;

wherein, in Formula 9,

is the same as in Formula 8, and

is L′, wherein L′ is one selected from groups represented by Formula 2a,

wherein, in Formula 2a,

a is an integer from 1 to 10,

R1 is a C1-C5 alkylene group,

R0 and R2 to R6 are each independently a C1-C10 alkyl group, a C6-C10 aryl group, or a C1-C10 heteroaryl group,

k is an integer from 1 to 10,

l is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom.

2. The polymer electrolyte of claim 1 , wherein an amount of the ion-conductive polymer having an unsaturated functional group at a terminal thereof is from about 0.1 part to about 50 parts by weight based on 100 parts by weight of the polymer having an unsaturated functional group at a terminal thereof and a fluoroalkylene chain.

3. The polymer electrolyte of claim 1 , wherein L 2 in Formula 3 is a group represented by Formula 3a:

—(CF 2 O) p (CF 2 CF 2 O) q (CFYO) r (CF 2 CFYO) s —(CF 2 (CF 2 ) z CF 2 O) t —  Formula 3a

wherein, in Formula 3a,

Y is a C1-C5 perfluoroalkyl group or a C1-C5 perfluoroalkyloxygroup,

z is 1 or 2, and

p, q, r, s, and t are each independently selected from 0 and a positive integer such that the weight average molecular weight of L 2 is about 500 to about 4,000 grams per mole.

4. The polymer electrolyte of claim 1 , wherein L 2 in Formula 3 is a group represented by Formula 3b:

—(CF 2 O) p (CF 2 CF 2 O) q —  Formula 3b

wherein, in Formula 3b,

p and q are each independently selected from 0 and a positive integer such that the weight average molecular weight of L 2 is about 500 to 4,000 grams per mole.

5. The polymer electrolyte of claim 1 , wherein A 1 and A 2 in Formula 3 are each a group represented by the following formula:

* denotes a binding site to a neighboring atom.

6. The polymer electrolyte of claim 1 , wherein the compound represented by Formula 3 is a compound represented by Formula 4 or Formula 5:

wherein, in Formula 4, R 1 , R 2 , A 1 , n, m, L 2 , and A 2 are the same as in Formula 3, and

in Formula 5, R 1 , R 2 , Al n, m, L 2 , and A 2 are the same as in Formula 3, and

R is a C1-C5 alkylene group.

7. The polymer electrolyte of claim 1 , wherein the compound represented by Formula 3 is at least one selected from H 2 C═C(CH 3 )COOCH 2 CH 2 NHCOOCH 2 CF 2 O(CF 2 CF 2 O) p′ (CF 2 O) q′ CF 2 CH 2 OCONHCH 2 C H 2 OCOC(CH 3 )═CH 2 (wherein p′ and q′ are each independently selected such that the weight average molecular weight of L 2 is about 500 to 4,000 grams per mole), a compound represented by Formula 6, a compound represented by Formula 7, and a compound represented by Formula 17a:

wherein, in Formula 6,

m is an integer of 1 to 5, and

n is an integer from 1 to 5,

wherein, in Formula 7,

m is an integer from 1 to 5, and

n is an integer from 1 to 5,

wherein, in Formula 17a, p and q are each independently selected such that the weight average molecular weight of a perfluoropolyether backbone —CF 2 (CF 2 O) p (CF 2 CF 2 O) q CF 2 — is about 500 to 4,000 grams per mole.

8. The polymer electrolyte of claim 1 , wherein the compound represented by Formula 1 and the compound represented by Formula 2 are each independently at least one selected from compounds represented by Formulae 15 to 19:

wherein, in Formula 15, n is an integer from 1 to 10,

wherein, in Formula 16, n is an integer from 1 to 10,

wherein, in Formula 17, n is an integer from 1 to 10,

wherein, in Formula 18,

n is an integer from 1 to 10, and

R is a C1-C5 alkyl group,

wherein, in Formula 19,

n is an integer from 1 to 10, and

R is a C1-C5 alkyl group.

9. The polymer electrolyte of claim 1 , wherein, in Formulas 8 and 9,

is one selected from groups represented by Formula 10:

wherein, in Formula 10,

a wavy-lined region is a C5-C40 cycloaliphatic urethane group, and

m and n are each independently an integer from 1 to 10.

10. The polymer electrolyte of claim 1 , wherein, in Formula 8,

is one selected from groups represented by Formula 11:

wherein, in Formula 11,

a is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom.

11. The polymer electrolyte of claim 1 , wherein, in Formula 9,

is one selected from groups represented by Formula 12:

wherein, in Formula 12,

a is an integer from 1 to 10,

* denotes a binding site to a neighboring atom,

k is an integer from 1 to 10, and

l is an integer from 1 to 10.

12. The polymer electrolyte of claim 9 , wherein the C5-C40 cycloaliphatic urethane group is a group represented by the following formula:

13. The polymer electrolyte of claim 1 , wherein the polymerization product is a compound represented by Formula 13, a compound represented by Formula 13b, or a compound represented by Formula 14:

wherein, in Formula 13,

a is an integer from 1 to 10,

m and n are each independently an integer from 30 to 100,

l and k are each independently an integer from 50 to 100, and

R 0 , R 1 , and R 2 are each independently a hydrogen, a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, or a pentyl group,

wherein, in Formula 13b,

m and n are each independently an integer from 30 to 100,

l and k are each independently an integer from 50 to 100, and

R 0 , R 1 , and R 2 are each independently a hydrogen, a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, or a pentyl group,

A is —(CF 2 O) a —

a is an integer from 1 to 10,

wherein, in Formula 14,

La is a group represented by Formula 14a,

m is an integer from 1 to 10,

m 1 is an integer from 30 to 100,

n is an integer from 30 to 100,

l is an integer from 50 to 100,

k is an integer from 50 to 100, and

R 1 , and R 2 are each independently a hydrogen, a methyl group, an ethyl group, a propyl group, an iso-propyl group, a butyl group, or a pentyl group:

wherein, in Formula 14a,

a is an integer from 1 to 5, and

* denotes a binding site to a neighboring atom.

14. The polymer electrolyte of claim 1 , wherein the polymer electrolyte further comprises a liquid electrolyte, and wherein a solvent impregnation ratio of the liquid electrolyte with respect to the polymerized product is about 5 percent by weight or less, wherein the solvent is at least one selected from ethylene carbonate, propylene carbonate, dimethylformamide, tetrahydrofuran, and chloroform.

15. The polymer electrolyte of claim 1 , wherein the polymer electrolyte further comprises a lithium salt.

16. The polymer electrolyte of claim 14 , wherein the lithium salt is at least one selected from LiSCN, LiN(CN) 2 , LiClO 4 , LiBF 4 , LiAsF 6 , LiPF 6 , LiCF 3 SO 3 , Li(CF 3 SO 2 ) 2 N, Li(CF 3 SO 2 ) 3 C, Li(FSO 2 ) 2 N, LiC 4 F 9 SO 3 , LiN(SO 2 CF 2 CF 3 ) 2 , LiSbF 6 , LiPF 3 (CF 2 CF 3 ) 3 , LiPF 3 (CF 3 ) 3 , LiCl, LiF, LiBr, LiI, lithium difluoro(oxalato)borate and lithium bis(oxalato)borate.

17. The polymer electrolyte of claim 1 , wherein the polymer electrolyte has an ion conductivity of about 10 −6 siemens per centimeter or greater at about 25° C.

18. The polymer electrolyte of claim 1 , wherein the polymer electrolyte has an oxidation potential of about 4.3 volts or greater and a Young's modulus of about 1 gigapascals or greater.

19. The polymer electrolyte of claim 1 , wherein the polymer electrolyte further comprises at least one selected from an organic solvent, an ionic liquid, a polymer ionic liquid, and an inorganic particle.

20. A lithium metal battery comprising:

a positive electrode;

a negative electrode comprising a lithium metal or a lithium metal alloy; and

the polymer electrolyte of claim 1 .

21. The lithium metal battery of claim 20 , wherein the lithium metal battery further comprises a lithium deposit layer on an upper surface of the negative electrode, wherein the lithium deposit layer has a deposition density of about 0.2 to 0.4 grams per cubic centimeter.

22. The lithium metal battery of claim 20 , wherein the lithium metal battery has a driving voltage of about 4 volts or greater.

23. A method of preparing a polymer electrolyte of any one of claims 1 to 19 , the method comprising:

polymerizing a mixture of a polymer comprising an unsaturated functional group at a terminal thereof and a fluoroalkylene chain, and an ion-conductive polymer comprising an unsaturated functional group at a terminal thereof, wherein the ion-conductive polymer comprising an unsaturated functional group at a terminal thereof is a polymer represented by Formula 1 or Formula 2, and wherein the polymer comprising an unsaturated functional group at a terminal thereof and a fluoroalkylene chain is a compound represented by Formula 3:

wherein, in Formula 1,

R 1 and R 2 are each independently a hydrogen or a C1-C5 alkyl group, and

L is one selected from groups represented by Formula 1a,

wherein, in Formula 1a,

R 1 is a C1-C5 alkylene group,

R 2 and R 3 are each independently a C1-C5 alkyl group,

a is an integer from 1 to 10,

k is an integer from 1 to 10,

l is an integer from 1 to 10,

n is an integer from 1 to 10, and

indicates denotes a binding site to a neighboring atom,

wherein, in Formula 2,

R 1 is a hydrogen or a C1-C5 alkyl group, and

L′ is one selected from groups represented by Formula 2a,

wherein, in Formula 2a,

a is an integer from 1 to 10,

R 1 is a C1-C5 alkylene group,

R 0 , and R 2 to R 6 are each independently a C1-C10 alkyl group, a C6-C10 aryl group, or a C1-C10 heteroaryl group,

k is an integer from 1 to 10,

l is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom,

wherein, in Formula 3,

L 1 and L 3 are each independently a bond or —C(═O)O—R—NH—, wherein R is a divalent, trivalent or tetravalent group and selected from a C1-C20 aliphatic hydrocarbon group, a C5-C40 cycloaliphatic group, a C5-C40 cycloaliphatic urethane group, a C6-C40 aryl group, and a C2-C40 heteroaryl group,

A 1 and A 2 are each independently a bond or a divalent, trivalent or tetravalent bonding group,

L 2 is a fluoropolyalkylene oxide chain or a perfluoropolyalkylene oxide chain,

R 1 and R 2 are each independently a hydrogen or a C1-C5 alkyl group, and n and m are each independently an integer from 1 to 3.

24. A polymer electrolyte comprising a polymerization product of:

a polymer comprising an unsaturated functional group at a terminal thereof and a fluoroalkylene chain, and

an ion-conductive polymer comprising an unsaturated functional group at a terminal thereof,

wherein the polymer having an unsaturated functional group at a terminal thereof and a fluoroalkylene chain is a compound represented by Formula 3:

wherein, in Formula 3,

L 1 and L 3 are each independently a bond or —C(═O)O—R—NH—, wherein R is a divalent, trivalent or tetravalent group and selected from a C1-C20 aliphatic hydrocarbon group, a C5-C40 cycloaliphatic group, a C5-C40 cycloaliphatic urethane group, a C6-C40 aryl group, and a C2-C40 heteroaryl group,

A 1 and A 2 are each independently a bond or a divalent, trivalent or tetravalent bonding group, and A 1 and A 2 in Formula 3 are each independently a C5-C40 cycloaliphatic urethane group,

L 2 is a fluoropolyalkylene oxide chain or a perfluoropolyalkylene oxide chain,

R 1 and R 2 are each independently a hydrogen or a C1-C5 alkyl group, and

n and m are each independently an integer from 1 to 3;

wherein the ion-conductive polymer comprising an unsaturated functional group at a terminal thereof is a polymer represented by Formula 1 or Formula 2,

wherein, in Formula 1,

R 1 and R 2 are each independently a hydrogen or a C1-C5 alkyl group, and L is one selected from groups represented by Formula 1a,

wherein, in Formula 1a,

R 1 is a C1-C5 alkylene group,

R 2 and R 3 are each independently a C1-C5 alkyl group,

a is an integer from 1 to 10,

k is an integer from 1 to 10,

l is an integer from 1 to 10,

n is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom,

wherein, in Formula 2,

R 1 is a hydrogen or a C1-C5 alkyl group, and

L′ is one selected from groups represented by Formula 2a,

wherein, in Formula 2a,

a is an integer from 1 to 10,

R 1 is a C1-C5 alkylene group,

R 0 and R 2 to R 6 are each independently a C1-C10 alkyl group, a C6-C10 aryl group, or a C1-C10 heteroaryl group,

k is an integer from 1 to 10,

l is an integer from 1 to 10, and

* denotes a binding site to a neighboring atom.