Green Composite Papers via Use of Natural Binders and Graphene for PEM Fuel Cell Electrodes

Herein a new fabrication method is suggested via a paper molding process for the preparation of graphene/cellulose/carbon fiber composite paper to be used as the flexible electrode layers mainly for PEM fuel cells. As a green and eco-friendly process, composite papers were prepared at ease with no pollutant by product formation by using ionic liquids (IL). At first, carbon fibers bound via cellulose fiber to form a cellulose/carbon fiber composite paper by wet-laying. Then, electrical conductivity as well as hydrophobicity of the composite papers were improved by extraction of cellulose via an ionic liquid-assisted phase inversion method and then graphene inserted into the structure of ionic liquid treated composite paper by spray coating. Moreover, by spray coating of 0.5 mg cm–2 platinum (Pt) catalyst to the mentioned composite papers, significant improvement in their fuel cell performances were achieved at low relative humidity (RH) fuel cell operation conditions (RH < 50%) which increases the overall system efficiency. The highest power density was recorded at 50% RH as 911 mW cm–2, which was over 20% higher than the 100% RH operating conditions.