Polymer electrolyte membrane, method for manufacturing same, and membrane electrode assembly comprising same

The polymer electrolyte membrane, wherein

• each of the first ion conductor and the second ion conductor is a fluorinated polymer comprising a fluorinated carbon backbone and a side chain represented by Chemical Formula 1 below, and
• the first ion conductor and the second ion conductor have different side-chain lengths,
• [Chemical Formula 1]
• —(OCF2CFRf)a—O—(CF2)b—X
• in Chemical Formula 1 above,
• Rf is respectively and independently one selected from a group consisting of F, Cl, and a perfluorinated alkyl group having a carbon number ranging from 1 to 10,
• X is an ion-exchanging group,
• a is a real number ranging from 0 to 3, and
• b is a real number ranging from 1 to 5.

A method of manufacturing a polymer electrolyte membrane, the method comprising:

• preparing a porous support having first and second surfaces opposite to each other, the porous support including a first portion having the first surface and a second portion having the second surface;
• filling first pores in the first region of the porous support with a first ion conductor to form a first layer;
• forming a first ion conductor layer on the first surface of the porous support with the first ion conductor;
• filling second pores in the second region of the porous support with a second ion conductor to form a second layer;
• and
• forming a second ion conductor layer on the second surface of the porous support with the second ion conductor, wherein
• the first ion conductor has a lower equivalent weight (EW) than the second ion conductor,
• a ratio of first thickness to second thickness is 9:1 to 6:4, the first thickness being a sum of a thickness of the first layer and a thickness of the first ion conductor layer, the second thickness being a sum of a thickness of the second layer and a thickness of the second ion conductor layer, and
• one selected from a group consisting of the first layer, the second layer, and a combination thereof includes an antioxidant.