Reversibility of Hydrogen Storage in Novel Complex Hydrides

摘要

A comparison of the hydrogen release and uptake (cycling) capability of Ti-doped NaAlH4, LiAlH4 and Mg(AlH4)2 as a function of Ti dopant concentration, temperature, pressure, and cycle number is reported. Temperature programmed desorption revealed hydrogen release capacities of around 3 wt% at 140 deg C, 3 wt% at 100 deg C and 6 wt% at 150 deg C, respectively, for the Ti doped Na, Li and Mg alanates. In the same order, release capacities of 0.5, 2.0 and 1.5 wt% were obtained in 150, 6 and 150 min during constant temperature desorption at 90 deg C. Although all three alanates exhibit striking characteristics that make them potential hydrogen storage materials, it remains that only Ti-doped NaAlH4 exhibits around 3 wt% reversibility under reasonable conditions.