Composition for gel polymer electrolyte and lithium secondary battery including gel polymer electrolyte formed therefrom

1. A composition for a gel polymer electrolyte, the composition comprising a lithium salt, a non-aqueous organic solvent, a polymerization initiator, and an oligomer,

wherein the oligomer comprises at least one selected from the group consisting of oligomers represented by Formula 1 and Formula 2:

wherein, in Formula 1,

R′ and R″ are each independently an aliphatic hydrocarbon group or an aromatic hydrocarbon group,

R 1 is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, —CO—O—R—, where R is an alkylene group having 1 to 10 carbon atoms, —R o —CO—, where R o is an alkylene group having 1 to 10 carbon atoms, or —R i —O—R′ i —, where R i and R′ i are each independently a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms,

R 2 is —CO—O—R 3 —O—, where R 3 is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, —CO—O—R—, where R is an alkylene group having 1 to 10 carbon atoms, —R j —CO—, where R j is an alkylene group having 1 to 10 carbon atoms, or —R k —O—R′ k —, where R k and R′ k are each independently a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, or —R 4 —CO—O—, where R 4 is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms),

R a , R b , R c , and R d are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms,

n is an integer of 1 to 100, and

m is an integer of 1 to 100,

a and c are each independently an integer of 0 to 2, and

b and d are each independently an integer of 1 to 3:

wherein, in Formula 2,

R 5 , R 6 , R 7 , and R 8 are each independently a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 20 carbon atoms, a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 20 carbon atoms, —CO—O—R m —, where R m is an alkylene group having 1 to 10 carbon atoms, —R n —CO—, where R n is an alkylene group having 1 to 10 carbon atoms, or —R 12 —O—R 13 —, where R 12 and R 13 are each independently a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms,

R 9 , R 10 , and R 11 are each independently an aliphatic hydrocarbon group or an aromatic hydrocarbon group,

R e , R f , R g , and R h are each independently hydrogen or an alkyl group having 1 to 3 carbon atoms,

o is an integer of 1 to 100,

p is an integer of 1 to 100, and

q is an integer of 1 to 100,

a1 and c1 are each independently an integer of 0 to 2, and

b1 and d1 are each independently an integer of 1 to 3.

2. The composition for a gel polymer electrolyte of claim 1 , wherein, in Formula 1,

R′ and R″ are aliphatic hydrocarbon groups,

R 1 is at least one selected from the group consisting of a substituted or unsubstituted alkylene group having 2 to 8 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 15 carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 10 carbon atoms, —CO—O—R—, where R is an alkylene group having 2 to 8 carbon atoms, —R o —CO—, where R o is an alkylene group having 2 to 8 carbon atoms, and —R i —O—R′ i —, where R 1 and R′ i are each independently a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, and

R 2 is —CO—O—R 3 —O—, where R 3 is a substituted or unsubstituted alkylene group having 2 to 8 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 15 carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 10 carbon atoms, —CO—O—R—, where R is an alkylene group having 1 to 10 carbon atoms, —R j —CO—, where R j is an alkylene group having 2 to 8 carbon atoms, or —R k —O—R′ k —, where R k and R′ k are each independently a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, or —R 4 —CO—O—, where R 4 is a substituted or unsubstituted alkylene group having 2 to 8 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 15 carbon atoms, or a substituted or unsubstituted heterocycloalkylene group having 2 to 10 carbon atoms.

3. The composition for a gel polymer electrolyte of claim 1 , wherein, in Formula 1,

R 1 is at least one selected from the group consisting of a propylene group, a butylene group, a pentylene group, a hexylene group, a cyclopentylene group, a cyclohexylene group, —CO—O—(CH 2 ) 5 —, —(CH 2 CH 2 OCH 2 CH 2 ) r —, where r is an integer of 1 to 10, and —(CH 2 ) 5 —CO—, and

R 2 is at least one selected from the group consisting of —CO—O—R 3 —O— (where R 3 is a propylene group, a butylene group, a pentylene group, a hexylene group, a cyclopentylene group, a cyclohexylene group, or —(CH 2 CH 2 OCH 2 CH 2 ) r1 , where r1 is an integer of 1 to 10, and —(CH 2 ) 5 —CO—O—.

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

wherein, in Formula 1a,

n1 is an integer of 1 to 100, and

m1 is an integer of 1 to 100;

wherein, in Formula 1b,

n2 is an integer of 1 to 100, and

m2 is an integer of 1 to 100;

wherein, in Formula 1c,

n3 is an integer of 1 to 100, and

m3 is an integer of 1 to 100.

5. The composition for a gel polymer electrolyte of claim 1 , wherein, in Formula 2,

R 9 , R 10 , and R 11 are aliphatic hydrocarbon groups, and

R 5 , R 6 , R 7 , and R 8 are each independently at least one selected from the group consisting of a substituted or unsubstituted alkylene group having 2 to 8 carbon atoms, a substituted or unsubstituted cycloalkylene group having 4 to 10 carbon atoms, a substituted or unsubstituted arylene group having 6 to 15 carbon atoms, a substituted or unsubstituted heterocycloalkylene group having 2 to 10 carbon atoms, —CO—O—R m —, where R m is an alkylene group having 2 to 8 carbon atoms), —R n —CO—, where R n is an alkylene group having 2 to 8 carbon atoms, and —R 12 —O—R 13 —, where R 12 and R 13 are each independently a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms.

6. The composition for a gel polymer electrolyte of claim 1 , wherein, in Formula 2, R 5 , R 6 , R 7 , and R 8 are each independently at least one selected from the group consisting of a propylene group, a butylene group, a pentylene group, a hexylene group, a cyclopentylene group, a cyclohexylene group, —CO—O—(CH 2 ) 5 —, —(CH 2 CH 2 OCH 2 CH 2 ) r2 —, where r2 is an integer of 1 to 10, and —(CH 2 ) 5 —CO—.

7. The composition for a gel polymer electrolyte of claim 1 , wherein the oligomer represented by Formula 2 comprises at least one selected from the group consisting of compounds represented by Formula 2a:

wherein, in Formula 2a,

o1 is an integer of 1 to 100,

p1 is an integer of 1 to 100, and

q1 is an integer of 1 to 100.

8. The composition for a gel polymer electrolyte of claim 1 , wherein the oligomer is included in an amount of 0.1 wt % to 35 wt % based on a total weight of the composition for a gel polymer electrolyte.

9. The composition for a gel polymer electrolyte of claim 1 , wherein the oligomer is included in an amount of 0.5 wt % to 30 wt % based on a total weight of the composition for a gel polymer electrolyte.

10. A gel polymer electrolyte comprising a polymerized compound of the composition for a gel polymer electrolyte of claim 1 .

11. A lithium secondary battery comprising the gel polymer electrolyte of claim 10 .