Light metal hydrides as hydrogen storage system for fuel cell power trains

The storage on solid materials appears a very interesting option for realization of hydrogen tank in fuel cell vehicles. In this paper the desorption properties of light metal hydrides are discussed evaluating hydrogen release rate as function of temperature. In particular the compound LiAlH4 (lithium alanate) was examined in this work, since it appears interesting for its high hydrogen content (10.5 wt%) and desorption kinetic properties at moderate temperatures. The properties of lithium alanate as hydrogen source for fuel cells were investigated in laboratory tests using a fixed bed reactor and nitrogen as carrier gas. The overall hydrogen release resulted about 7% in two successive steps (decomposition of LiAlH4, followed by decomposition of Li3AlH6) characterised by different kinetics, in a temperature range of 140-160 °C for the first decomposition and 180-210 °C for the second. Moreover, a laboratory device was designed and realized to use light metal hydrides as hydrogen source in fuel cell propulsion systems for road applications.