Organic-inorganic composite anion exchange membrane containing polyvinylidene fluoride polymer for non-aqueous redox flow battery and method for preparing the same

1. An anion exchange membrane for non-aqueous redox flow batteries, comprising:

(A) silica particles;

(B) a polyvinylidene fluoride polymer represented by Formula 1:

(where l is an integer ranging from 5,000 to 500,000); and

(C) a divinylbenzene polymer,

wherein

the silica particles are present in an amount ranging from 5 wt % to 10 wt % based on the amount of polyvinylidene fluoride polymer,

the silica particles have a particle size ranging from 5 nm to 20 nm, and

the divinylbenzene polymer is a polymer having a structure selected from structures represented by Formulae 3, 3a, 3b, or a mixture thereof:

where m is an integer ranging from 1 to 500,000, and 1≤x+y≤500,000, and x and y are integers;

where two x's are identical or different from each other, four y's are identical or different from one another, m is an integer ranging from 1 to 500,000, and 1≤x+y≤500,000, and x and y are integers; and

where four x's are identical or different from each other, four y's are identical or different from one another, m is an integer ranging from 1 to 500,000, and 1≤x+y≤500,000, and x and y are integers,

wherein in Formulae 3, 3a, and 3b:

R 1 is at least one selected from the group consisting of a pyridine cation substituted with a linear or branched C 1 to C 6 alkyl group, a pyrrole cation substituted with a linear or branched C 1 to C 6 alkyl group, an indole cation substituted with a linear or branched C 1 to C 6 alkyl group, a carbazole cation substituted with a linear or branched C 1 to C 6 alkyl group, a pyrimidine cation substituted with a linear or branched C 1 to C 6 alkyl group, an imidazole pyridinyl cation substituted with a linear or branched C 1 to C 6 alkyl group, and a pyrazolyl cation substituted with a linear or branched C 1 to C 6 alkyl group,

R 2 is H or CH 3 .

2. The anion exchange membrane for non-aqueous redox flow batteries according to claim 1 , wherein

m is an integer ranging from 1 to 100,000; and

1≤x+y≤100,000, and x and y are integers.

3. The anion exchange membrane for non-aqueous redox flow batteries according to claim 1 , wherein R 1 is at least one selected from among

m is an integer ranging from 1 to 100,000; and

1≤x+y≤100,000, and x and y are integers.

4. The anion exchange membrane for non-aqueous redox flow batteries according to claim 1 , wherein the initiator comprises at least one selected from among benzoyl peroxide, acetyl peroxide, lauroyl peroxide, 2,2′-azobisisobutyronitrile, tert-butyl peroxide, 4,4-azobis(4-cyanovaleric acid), 1,1′-azobis(cyclohexanecarbonitrile), and tert-butyl peracetate.

5. The anion exchange membrane for non-aqueous redox flow batteries according to claim 1 , wherein the anion exchange membrane has a thickness of 10 μm to 100 μm.

6. The anion exchange membrane for non-aqueous redox flow batteries according to claim 1 , wherein the anion exchange membrane has an ionic conductivity of 2.4×10 −4 S/cm or more, and the ionic conductivity is calculated according to Equation 4:

Ion

⁢

⁢

conductivity

⁢

⁢

(

S

⁢

/

⁢

cm

)

=

l

MER

,

〈

Equation

⁢

⁢

4

〉

wherein l is a thickness of the membrane and MER is resistance of the membrane.

7. A non-aqueous redox flow battery, comprising:

a positive electrolyte;

a negative electrolyte; and

the anion exchange membrane according to claim 1 , the anion exchange membrane being disposed between the positive electrolyte and the negative electrolyte.