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<sup>–2</sup> 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<sup>–2</sup>, which was over 20% higher than the 100% RH operating conditions.