METHOD FOR THE PREPARATION OF CATALYST-COATED MEMBRANES METHOD FOR THE PREPARATION OF CATALYST-COATED MEMBRANES

摘要

The present invention is directed to a method for preparing an integral 3-layer catalyst-coated membrane (CCM) for use in electrochemical cells, e.g. PEM (polymer-electrolyte membrane) fuel cells. The process comprising the steps of preparing a first catalyst layer on a supporting substrate, subsequently coating the first catalyst layer with an ionomer dispersion to form an ionomer layer (membrane), and applying a second catalyst layer on top of the ionomer layer. The ionomer dispersion applied in the membrane coating step has low viscosity in the range of 10 to 400 centipoises (cP) and an ionomer concentration in the range of 15 to 35 weight-%. With this method, CCMs with improved electrochemical performance and reduced cathode resistance are manufactured.

主权项

1. Method for preparing a 3-layer catalyst-coated membrane (CCM) comprising a first catalyst layer, an ionomer membrane and a second catalyst layer, said method comprising the steps of
a) preparing a first catalyst layer on a supporting substrate, b) coating the first catalyst layer with an ionomer dispersion to form an ionomer membrane in contact with the first catalyst layer, c) applying the second catalyst layer on top of the ionomer membrane, wherein the ionomer dispersion applied in step b) has a viscosity in the range of 10 to 400 centipoise (cP) and an ionomer concentration in the range of 15 to 35 wt.-%.