title: Ultrahigh PEMFC performance of a thin-film, dual-electrode assembly with tailored electrode morphology.
abstract: A dual-electrode membrane electrode assembly (MEA) for proton exchange membrane fuel cells with enhanced polarization under zero relative humidity (RH) is fabricated by introducing a phase-separated morphology in an agglomerated catalyst layer of Pt/C (platinum on carbon black) and Nafion. In the catalyst layer, a sufficient level of phase separation is achieved by dispersing the Pt catalyst and the Nafion dispersion in a mixed-solvent system (propane-1,2,3-triol/1-methyl-2-pyrrolidinone).The high polymer chain mobility results in improved water uptake and regular pore-size distribution with small pore diameters. The electrochemical performance of the dual-film electrode assembly with different levels of phase separation is compared to conventional electrode assemblies. As a result, good performance at 0 % RH is obtained because self-humidification is dramatically improved by attaching this dense and phase-separated catalytic overlayer onto the conventional catalyst layer. A MEA prepared using the thin-film, dual-layered electrode exhibits 39-fold increased RH stability and 28-fold improved start-up recovery time during the on-off operation relative to the conventional device. We demonstrate the successful operation of the dual-layered electrode comprised of discriminatively phase-separated agglomerates with an ultrahigh zero RH fuel-cell performance reaching over 95 % performance of a fully humidified MEA.
authors.affiliation: Department of Chemical Engineering, Hanyang University, Seoul 133-791 (Republic of Korea).
authors.forename: Chi-Young
authors.initials: CY
authors.lastname: Jung
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Kim
authors.forename: Sung-Chul
authors.initials: SC
authors.lastname: Yi
mesh_terms: D011211:Electric Power Supplies; D004566:Electrodes; D006813:Humidity; D006859:Hydrogen / Q000737:chemistry; D008567:Membranes, Artificial; D010100:Oxygen / Q000737:chemistry; D011522:Protons; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D011522:Protons; D014867:Water; D006859:Hydrogen; D010100:Oxygen
keywords: fuel cells; phase separation; platinum; self-humidification; solvent effects