Fuel cell cathode catalyst layers from “green” catalyst inks
- 7 July 2008
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Energy & Environmental Science
- Vol. 1 (1), 184-193
- https://doi.org/10.1039/b808613n
Abstract
Fuel cell cathode catalyst layers deposited from a water-based catalyst ink formulation, using high water content and minimum volatile organic compounds, are investigated. Cathodes fabricated from a dispersion medium containing 96 wt% water are compared with cathodes fabricated from conventional alcohol-based inks containing 1-propanol–water 3 : 1 (w/w). The morphology of the two catalyst layers are similar, as are electrochemically-active surface areas at relative humidities of 100, 70 and 30% RH. Oxygen reduction kinetics obtained under fully humidified H2/O2 conditions exhibit similar Tafel slopes, 67 ± 3 mV per dec. However, cathodes prepared from water-based inks exhibit a lower H2/air fuel cell performance under 100, 70 and 30% RH while its porosity, obtained using mercury porosimetry, is slightly higher. EIS measurements obtained under high current density indicate that the mass transport resistance of the water-based catalyst layer is lower, which is consistent with porosimetric data, and suggests that factors other than mass transport limit the performance of the water-based cathode. The protonic resistance of the catalyst layers was found to be 105 and 145 mΩ cm2 for the propanol- and water-based catalyst layers, respectively. The differences are more pronounced when RH is decreased from 100 to 30%. This trend is consistent with the observed decrease in fuel cell performance under conditions of lower RH, and indicates that the higher proton resistance of the water-based catalyst layer is the cause of its lower fuel cell performance.Keywords
This publication has 29 references indexed in Scilit:
- Performance enhancement of PEMFC through temperature control in catalyst layer fabricationElectrochimica Acta, 2007
- Ethanol/water mixture permeation through a Nafion® based membrane electrode assemblyJournal of Power Sources, 2007
- Effect of Nafion® ionomer aggregation on the structure of the cathode catalyst layer of a DMFCJournal of Power Sources, 2007
- Morphology study of Nafion membranes prepared by solutions castingJournal of Polymer Science Part B: Polymer Physics, 2005
- Influence of the solvent in anode catalyst ink on the performance of a direct methanol fuel cellJournal of Power Sources, 2004
- Solution properties of nafion in methanol/water mixture solventPolymer, 2004
- Effect of Additives on Self-Assembling Behavior of Nafion in Aqueous MediaMacromolecules, 2001
- Equilibrium Aggregation in Perfluorinated Ionomer SolutionsMacromolecules, 1998
- Self-Assembling of Perfluorinated Polymeric Surfactants in Nonaqueous Solvents. Electron Spin Resonance Spectra of Nitroxide Spin Probes in Nafion Solutions and Swollen MembranesLangmuir, 1994
- Morphology and chemical properties of the Dow perfluorosulfonate ionomersMacromolecules, 1989