General Motors and Sandia National Laboratories of Livermore, CA, have launched a partnership to design and test an advanced method for storing hydrogen based on metal hydrides.

Sandia National Laboratories engineer Terry Johnson sets up a test apparatus that, when verified, will generate external heat that improves the overall energy density compared to traditional heat sources

Metal hydrides - formed when metal alloys are combined with hydrogen - can absorb and store hydrogen within their structures. When subjected to heat, the hydrides release their hydrogen. In a fuel cell system, the hydrogen can then be combined with oxygen to produce electricity.

GM and Sandia, a National Nuclear Security Administration lab, have embarked on a 4-year, $10 million program to develop and test tanks that store hydrogen in a complex hydride, sodium aluminum hydride - or sodium alanate for short. The goal is to develop a pre-prototype solid-state hydrogen storage tank that would store more hydrogen onboard a fuel cell vehicle than current conventional hydrogen storage methods. Researchers also hope to create a tank design that could be adaptable to any type of solid-state hydrogen storage.

GM and Sandia say the program is part of a concerted effort to find a way to store enough hydrogen onboard a fuel cell vehicle to equal the driving range obtained from a tank of gas, which will be key to customer acceptance of fuel cell vehicles.

The current leading methods of storage are liquid and compressed gas. However, to date, neither of these technologies has been able to provide the needed range and running time for fuel cell vehicles.

"We are designing a hydrogen storage system with challenging thermal management requirements and limits on volume and weight," says Chris Moen, manager of science and engineering technologies at Sandia. "Our staff researchers are excited to apply their unique, science-based design and analysis capabilities to engineer a viable solution."

"This is the kind of public private research partnership that will help us realize the President's vision, communicated in his 2003 State of the Union Address, that 'the first car driven by a child born today can be powered by hydrogen, and pollution-free,'" said DOE Secretary Spencer Abraham. "Over the long term, because of the President's visionary leadership, clean, efficient hydrogen fuel technologies like this will help make our nation far less reliant on foreign sources of energy."

In 2003, President Bush announced the Hydrogen Fuel Initiative with $1.2 billion over five years (FY 2004-FY 2008) to accelerate hydrogen research. Sandia’s research activities in hydrogen storage support the President’s long term vision for commercially viable hydrogen-powered vehicles to reverse America’s growing dependence on foreign oil. The GM-Sandia project is privately funded and separate from the President’s initiative.

A possible scenario for filling up with a solid-state storage solution such as sodium alanate could look like this: The alanate would come preloaded in the tank, where it would remain, giving up its hydrogen, and becoming a mixture of sodium hydride and aluminum. The customer would fill up using gaseous hydrogen. During filling, the mixture of aluminum and sodium hydride would absorb the hydrogen and turn it back into alanate, which would be ready to yield hydrogen when needed by the fuel cell. Once the tank is filled, the hydrogen would be stored at low pressure.

In separate, independent projects outside of this collaboration, both GM and Sandia are working to identify alloys that will store greater amounts of hydrogen that can be released at lower temperatures. Reducing filling and recharging times is another key area of research.

The research conducted through the GM-Sandia partnership is independent from that of Sandia's participation in the Metal Hydride Center of Excellence. The Center of Excellence, funded in Fiscal Year 2005 through a U.S. Department of Energy "Grand Challenge," aims to develop a new class of materials capable of storing hydrogen safely and economically.

Contact: Mike Janes 925- 294-2447