Method of manufacturing membrane-electrode assembly by directly coating electrode layer on electrolyte membrane

A method of manufacturing a membrane-electrode assembly, the method comprising:

• forming an electrolyte membrane containing an ionomer on a base material;
• applying an electrode slurry, which contains a catalyst, a binder, and a solvent, to a first surface of the electrolyte membrane to form a structure including the electrolyte membrane and an electrode layer laminated on the first surface of the electrolyte membrane;
• and
• delaminating the structure from the base material,
• wherein the ionomer contains a perfluorinated sulfonic acid-based polymer expressed by Formula 1 below:
• wherein m is 4.2, n is 1, x is 0, and y is 2,
• the method further comprising, after the forming the electrolyte membrane:
• performing heat treatment on a resultant of the electrolyte membrane and the base material;
• and
• adjusting delamination strength between the base material and the electrolyte membrane to 7.32 gf/mm or more and 10 gf/mm or less,
• wherein the heat treatment is performed in a condition in which a temperature ranges from 100° C. to 160° C.,
• wherein the solvent includes a mixture in which an aqueous solvent is mixed with an organic solvent in a mass ratio ranging from 5:5 to 8:2,
• wherein, in a condition in which a temperature ranges from 30° C. to 100° C. and relative humidity (RH) ranges from 50% to 100%, the structure is exposed for three seconds or more and delaminated from the base material.