TransForum Vol. 6, No. 1

Hydrogen + Advances in Fuel Cell Technology = Clean, Efficient Transportation

Argonne's Fuel Cell Test Facility, operational since 1998, has capabilities for evaluating full-size automotive fuel cell stacks and complete reformer/fuel cell systems with power rating of up to 80 kW. Shown here: Engineers check a proton-exchange-membrane (PEM) fuel cell stack before starting a test.

Hydrogen is an ideal energy carrier for fuel cells, which offer a clean, efficient power source for transportation. Argonne works closely with the U.S. Department of Energy (DOE) to develop materials, processes, and systems for polymer electrolyte and solid oxide fuel cell systems, as well as hydrogen production, delivery, and storage options.

Specifically, Argonne researchers are focusing on:

• Advanced fuel processing in integrated fuel cell power systems;
• Improved, lower-cost materials for fuel cells;
• Enhanced fuel cell designs; and
• Hydrogen production pathways, delivery system alternatives, and storage.

To support these R&D initiatives, Argonne's Fuel Cell Test Facility offers independent, standardized testing and evaluation of all fuel cell types for DOE and fuel cell developers. The only such facility in the national laboratory system, it is one of the few in the nation that can test full, automotive-sized systems.

Fuel Processing Innovations

Until hydrogen is readily available, fuel cells could operate on conventional fuels, such as natural gas, propane, gasoline, and diesel, or alternative fuels, such as methanol, ethanol, and bio-diesel. Such fuels can be converted to hydrogen or a hydrogen-containing gas mixture through a series of chemical reactions in fuel reformers (also known as fuel processors).

Several Argonne R&D initiatives in fuel processing are under way. In one effort, a team of scientists and engineers has developed and patented a compact fuel processor that reforms conventional fuels into a hydrogen-rich gas to power fuel cells. The device is energy efficient, capable of rapid start-up and shut-down, and dynamically responsive to load changes. Sud-Chemie (Louisville, Kentucky) has licensed the reforming catalyst technology.

Argonne researchers are also exploring technology to reform diesel fuel for use in fuel cell applications. For instance, tractor-trailer trucks soon could be using diesel to create the hydrogen needed for clean, quiet, fuel-cell-powered auxiliary-powered units (APUs). The APU would generate power for air conditioners and other hotel loads when the main engine is shut off. The researchers are collaborating with three university teams to address materials and fuel processing issues.

In yet another effort, Argonne is developing a ceramic membrane to efficiently and inexpensively extract hydrogen from fossil fuels. The membrane operates at higher temperatures and under low-humidity conditions to reduce system cost, size, and complexity.

More Durable Materials

A major hurdle to commercializing polymer electrolyte fuel cell systems, especially for automotive use, is the high cost of the cell's platinum electrocatalysts. To address this barrier, Argonne chemists are working on low-cost, non-platinum electrocatalysts (employing bi-metallic base metal/noble metal systems) for the oxygen-reduction reaction. These durable materials would be stable in the fuel cell's operating environment and retain high electrochemical activity over the fuel cell’s design lifetime.

Better Fuel Cell Design

Improved fuel cell system design results in better operation and lower cost. GCtool and PSAT modeling software, created at Argonne, enables researchers to easily evaluate a myriad of fuel cell system designs, energy storage requirements, fuel economy, etc.

For solid oxide fuel cells, TuffCell, a novel design and fabrication process, decreases the stack cost and improves the mechanical strength, thermal cyclability, and seal durability. The design supports the cell on a rugged, inexpensive metal. TuffCell offers promise in APU applications for heavy-duty vehicles, enabling truck drivers to meet anti-idling legislation while improving their overall fuel economy.

Hydrogen Production, Delivery, and Storage

Argonne transportation analysts are evaluating various production and delivery system combinations to identify the best in terms of cost, safety, and energy efficiency. Their efforts were recognized in May with a DOE Hydrogen Program R&D Award "In Recognition of Outstanding Achievement in Delivery Analysis." (See FasTrax.) Researchers also are focusing on carbon-based materials for storage and analyzing hydrogen storage systems. A novel group of hydrogen adsorbent materials (nanostructured polymer and carbon) were developed with highly ordered layer structure on interstitial spaces at the nanometer scale. These materials were found to absorb significant quantities of hydrogen non-dissociatively via an enhanced van der Waals interaction.

The R&D initiatives described in this article are sponsored by DOE's Offices of Science, Energy Efficiency and Renewable Energy, Fossil Energy, and Nuclear Energy.

September 9, 2006