Polymer electrolyte membrane, membrane-electrode assembly comprising the same and fuel cell comprising the same
The present invention relates to a polymer electrolyte membrane, and a membrane-electrode assembly and a fuel cell containing the same, and the polymer electrolyte membrane comprises a polymer comprising repeating units represented by the following chemical formulas 1-3. Chemical formulas 1-3 are as defined in the specification. The polymer electrolyte membrane has excellent resistance to radical attack and has improved acid-base interaction, thereby maximizing the function of an ion conductive group, and thus can improve the operation performance of a fuel cell in a low humidification state.
1. A polymer electrolyte membrane comprising a polymer including repeat units represented by Formulae 1 to 3 below:
wherein A is an ion conducting group selected from the group consisting of a sulfonic acid group, a carboxylic acid group and a phosphoric acid group;
X is any one selected from the group consisting of a single bond, —CO—, —SO 2 —, —CONH—, —COO—, —CR′ 2 —, a cyclohexylidene group, a fluorenylidene group, —O— and —S— in which R′ is any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group and a nitrile group;
Y is a bivalent nitrogen-containing aromatic ring;
Z is —O— or —S—;
R 1 to R 14 are each independently any one selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group and a nitrile group; and
n is an integer of 0 to 4.
2. The polymer electrolyte membrane according to claim 1 , wherein the polymer comprises 100 parts by mole of the repeat unit represented by Formula 3, 1 to 200 parts by mole of the repeat unit represented by Formula 1 and 1 to 200 parts by mole of the repeat unit represented by Formula 2.
3. The polymer electrolyte membrane according to claim 1 , wherein the bivalent nitrogen-containing aromatic ring comprises any one selected from the group consisting of pyrrole, thiazole, isothiazole, oxazole, iso-oxazole, imidazole, imidazoline, imidazolidine, pyrazole, triazine, pyridine, pyrimidine, pyridazine, pyrazine, indole, quinoline, isoquinoline, tetrazole, tetrazine, triazole, carbazole, quinoxaline, quinazoline, indolizine, isoindole, indazole, phthalazine, naphthyridine, bipyridine, benzimidazole, imidazole, pyrrolidine, pyrroline, pyrazoline, pyrazolidine, piperidine, piperazine and indoline.
4. The polymer electrolyte membrane according to claim 1 , wherein the polymer further comprises a repeat unit represented by Formula 4 below:
wherein Z is —O— or —S—; and
R 15 to R 22 are each independently any one selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group and a nitrile group.
5. The polymer electrolyte membrane according to claim 4 , wherein the polymer comprises 100 parts by moles of the repeat unit represented by Formula 3, 1 to 200 parts by mole of the repeat unit represented by Formula 1, 1 to 200 parts by mole of the repeat unit represented by Formula 2, and 1 to 200 parts by mole of the repeat unit represented by Formula 4.
6. The polymer electrolyte membrane according to claim 1 , wherein the polymer further comprises repeat units represented by Formulae 5 and 6 below:
wherein A is an ion conducting group selected from the group consisting of a sulfonic acid group, a carboxylic acid group and a phosphoric acid group;
Y is a bivalent nitrogen-containing aromatic ring;
Z is —O— or —S—; and
R 1 to R 6 and R 15 to R 22 are each independently any one selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group and a nitrile group.
7. The polymer electrolyte membrane according to claim 6 , wherein the polymer further comprises repeat units represented by Formulae 7 and 8 below:
wherein A is an ion conducting group selected from the group consisting of a sulfonic acid group, a carboxylic acid group and a phosphoric acid group;
X is any one selected from the group consisting of a single bond, —CO—, —SO 2 —, —CONH—, —COO—, —CR′ 2 —, a cyclohexylidene group, a fluorenylidene group, —O— and —S— in which R′ is any one selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group and a nitrile group;
Z is —O— or —S—;
R 1 to R 22 are each independently any one selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a hydrogen atom, a halogen atom, an alkyl group, a halogenated alkyl group, an allyl group, an aryl group, a nitro group and a nitrile group; and
n is an integer of 0 to 4.
8. The polymer electrolyte membrane according to claim 1 , wherein the polymer electrolyte membrane comprises:
a porous support comprising nanofibers integrated in the form of a non-woven fabric including a plurality of pores; and
the polymer filling pores of the porous support.
9. A membrane-electrode assembly comprising:
an anode and a cathode which face each other; and
the polymer electrolyte membrane according to claim 1 disposed between the anode and the cathode.
10. A fuel cell comprising the membrane-electrode assembly according to claim 9 .
11. A membrane-electrode assembly comprising:
an anode and a cathode which face each other; and
the polymer electrolyte membrane according to claim 8 disposed between the anode and the cathode.
12. A fuel cell comprising the membrane-electrode assembly according to claim 11 .