Multilayer reinforced composite electrolyte membrane and method for manufacturing same

A method for manufacturing a multilayer reinforced composite electrolyte membrane, comprising:

• (a) a step of preparing an ionomer solution comprising 22-27 wt % of an ionomer;
• (b) a step of preparing a reinforced composite electrolyte membrane wherein two ionomer layers with a thickness of 5-15 μm are formed in contact with both sides of a porous support, respectively, by impregnating the porous support in the ionomer solution and then drying the same;
• (c) a step of stacking two or more of the reinforced composite electrolyte membranes and applying a pressure of 300-600 psi using a roll press to the two or more of the reinforced composite electrolyte membranes without applying heat;
• and
• (d) a step of applying heat and pressure of 1300-1800 psi at a temperature of 132-138° C. to the two or more of the reinforced composite electrolyte membranes to obtain the multilayer reinforced composite electrolyte membrane,
• wherein the two ionomer layers are the same as each other.