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The Priority and Challenge of High-Power Performance of Low-Platinum PEMFCs Anusorn Kongkanand, and Mark F. Mathias J. Phys. Chem. Lett., Just Accepted Manuscript • DOI: 10.1021/acs.jpclett.6b00216 • Publication Date (Web): 10 Mar 2016 Downloaded from http://pubs.acs.org on March 10, 2016
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The Journal of Physical Chemistry Letters
The Priority and Challenge of High-Power Performance of Low-Platinum PEMFCs Anusorn Kongkanand, Mark F. Mathias Fuel Cell Activities, General Motors Global Product Development, Pontiac, MI 48340
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ABSTRACT
Substantial progress has been made in reducing proton-exchange-membrane fuel cell (PEMFC) cathode platinum loadings from 0.4-0.8 mgPt/cm2 to about 0.1 mgPt/cm2. However, at this level of cathode Pt loading, large performance loss is observed at high-current density (>1 A/cm2), preventing a reduction in the overall stack cost. This next developmental step is being limited by the presence of a resistance term exhibited at these lower Pt loadings and apparently due to a phenomenon at or near the catalyst surface. This issue can be addressed through the design of catalysts with high and stable Pt dispersion as well as through development and implementation of ionomers designed to interact with Pt in a way that does not constrain oxygen reduction reaction rates. Extrapolating from progress made in past decades, we are optimistic that the concerted efforts of materials and electrode designers can resolve this issue, thus enabling a large step towards mass-market-affordable fuel cell vehicles.
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Thanks to substantial research and development in the last two decades, automotive manufacturers are now bringing proton-exchange membrane (PEM) fuel-cell electric vehicles (FCEV) to the market. Engineers have developed fuel-cell systems meeting automotive performance and durability requirements as well as resolved vehicle-integration challenges such as packaging, safety, and cold start. However, the fuel-cell system costs are still high when compared to the internal-combustion engine (ICE) incumbent. Some of the current high fuel-cell-system cost arises from manufacturing issues amenable to major reduction through economies of scale. However, precious metal costs, primarily Pt, in the electrocatalysts would not benefit from the economy of scale and might even increase at higher FCEV market penetration. Thus, the execution of a technical roadmap to reduce PEMFC Pt-use requirements is vital to the ultimate realization of the fuel-cell-vehicle market. The US Department of Energy (DOE) set a platinum-group-metal (PGM) target of 0.125 kWrated/gPGM or about 11.3 gPGM per mid-size-sedan-vehicle (90 kWgross) by year 2020.1 As a reference, the current clean light-duty ICE-vehicle catalytic converter generally requires
