January 3, 2008
Review panel suggests no more funding for sodium borohydride vehicular hydrogen storage
Golden, Colorado – An independent technical review panel, convened by the U.S. Department of Energy (DOE), has unanimously recommended “no go” on further funding for sodium borohydride for on-board vehicle hydrogen storage, according to a report by the Green Car Congress. A version of the sodium borohydride-based system was used on the DaimlerChrysler Natrium fuel cell concept car, introduced in 2001.
Millennium Cell and other companies have been working on sodium borohydride-based systems for a range of applications, from portable devices to transportation. The Natrium, based on a Chrysler Town & Country minivan, used a Millennium Cell fuel processor with Ballard fuel cell.
When sodium borohydride is suspended in an aqueous solution and passed over a catalyst, it produces hydrogen, along with sodium metaborate that can be recycled back into sodium borohydride. The panel reviewed materials from a number of researchers, including Penn State University, Material & Energy Research Institute Tokyo, and the DOE Chemical Hydrogen Storage Center of Excellence.
In its statement, the panel said that the hydrogen storage technology considered for the hydrolysis procedure has not met all of the 2007 targets, and would not appear to be able to reach all of the 2010 targets. While some status reports indicated system numbers that did meet 2007 targets, the panel found several concerns over the system’s practicality, including an unproven single-tank bladder system, the requirement for large amounts of water to be carried on the vehicle, and hydrogen costs above the target. However, the review panel did note that improvements to the sodium borohydride system did have application to the cost-effective production of an alternative borane-based on-board storage system, which is a major area of research at the DOE Chemical Hydrogen Storage Center of Excellence.