DefinePK

Abstract

Gas diffusion layer (GDL) plays an important role in polymer electrolyte membrane fuel cell (PEMFC). It provides diffusion media that transport reactant gas into catalyst layer, mechanical support for electrolyte membrane, electrical pathways for electron, and serves channel product water away from the electrode. In this study, the main physical properties (hydrophobicity, electrical conductivity, and porosity) and the performance of GDL made from activated carbon powder from coconut coir were investigated. Its properties were also compared to commercially available GDL, Toray TGP-H-120 (TGP-120). Gas diffusion layer coconut carbon paper (CCP) was fabricated by mixing the coconut carbon powder, ethylene vinyl acetate, polyethylene glycol, and xylene using hot plate stirrer at 100?C. The carbon slurry was casted to make carbon paper and then dried at room temperature. The carbon paper was also treated with PTFE solution to improve its hydrophobicity. SEM images showed that CCP had smoother surface morphology and denser compared to TGP-120, however, its porosity was quite similar, 69% and 74%, respectively. This was estimated because CCP had internal porous on the surface of coconut fibres. Although low conductivity of CCP still needed a further improvement, its relatively high hydrophobicity would be benefited the water management inside the cell. By measuring the cell performance in a single cell proton exchange membrane fuel cell (PEMFC) with an active area of 25 cm2 using H2/O2 reactants, CCP showed a good fuel cell performance with current density of about 232 mA/cm2 at 0.6 volt, compared to 284 mA/cm2 for TGP-120. Power peaks were revealed at 168 and 208 mW/cm2 for both CCP and TGP-120, respectively.