TECHNOLOGY
POLYMER
ELECTROLYTE
FUEL CELLS
Reformate Fuel Cells
Direct Methanol Fuel Cells
Air-breathing Fuel Cell Stacks
Adiabatic Fuel Cell Stacks
FUEL
PROCESSING
HIGH-TEMPERATURE
ELECTROCHEMISTRY
ASSOCIATED
TECHNOLOGIES
Advanced Chlor-alkali Reactors
PEM
Sensors
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Polymer electrolyte fuel cells (PEFCs) generally require pure hydrogen
fuel, but the difficulty in storing and distributing hydrogen limits
their practical use. To avoid this problem the DOC
Partnership for a New Generation of Vehicles (PNGV) has asked
that a gasoline-powered fuel cell be developed for use in automobiles.
A vehicle powered by this type of fuel cell could be refueled at
the same gas pump used for traditional gas engine cars.
Gas-powered
fuel cells are technically complex in that they require a fuel reformation
system that converts gasoline (or another hydrogen-containing fuel)
to hydrogen that the fuel cell can use. The hydrogen, carbon dioxide,
and additional trace components produced by the conversion process
are called reformate fuel.
The
Technology
The reformation
process typically involves the conversion of a hydrocarbon like
gasoline to a mixture of carbon dioxide, hydrogen, and trace levels
of other gases. Most non-hydrogen substances in the reformate act
as contaminants, poisoning the catalyst by limiting its ability
to ionize the hydrogen fuel. This catalyst limits the fuel cell’s
commercial availability. By limiting the catalyst’s susceptibility
to contamination, the fuel cells can operate more efficiently under
a wider variety of conditions.
Background
Since 1995 LANL fuel cell researchers have been working to improve
the performance of reformate fuel cells with technical objectives set
by the PNGV, etc.
At the start of the project, research focused on improving anode
performance and CO tolerance. The CO tolerance has been improved
by over two orders of magnitude, affecting a change in PNGV targets.
Current research is more focused on air electrodes in an effort
to improve the overall efficiency of the fuel cell system.
Accomplishments
Recent accomplishments include improved cathode
performance, greater CO tolerance, and advanced functionality during
system startup. Electrocatalytic advances have improved overall
efficiency while making the system more environmentally flexible
and less expensive to produce.
Research Objectives
Cathode improvement: increase achievable current density at 0.8V
Anode improvement: minimize the effects of dilution and
CO
Implement new activity related to high temperature membranes
Increase membrane/electrode assembly (MEA) durability with
accelerated lifetest protocols and brute force testing
Establish new MEA fabrication approaches
Complete segmented cell development and make the design
commercially available
Research
Approach
Researchers are working to better understand electrocatalysis and
transport issues related to cathode performance, and to use this
understanding to guide the development, testing, and demonstration
of improved electrodes.
We are striving to simultaneously achieve the following cell characteristics
through applied research and development:
Highest possible performance at 0.8 V
Minimum air injection for CO cleanup
Minimum catalyst loading
Minimum losses due to dilution at high fuel use
Goals
Improve polymer electrolyte fuel cell performance under conditions
appropriate for reformate/air operations
Develop methods that allow cost and efficiency targets
to be met for transportation
applications
Work toward the PNGV objectives
Diagnose long-term performance limitations
Point
of Contact
fuelcells@lanl.gov
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