Comparative study on the dehydrogenation properties of TiCl4-doped LiAlH4 using different doping techniques

Lithium aluminum hydride (LiAlH ₄) is an attractive hydrogen storage material because of its comparatively high gravimetric hydrogen storage capacity. In this study, titanium tetrachloride (TiCl ₄), which is liquid at room temperature, was chosen as dopant because of its high catalytic efficiency regarding the dehydrogenation of LiAlH ₄. Three low-energy doping methods (additive dispersion via ball milling at low rotation speed, magnetic stirring and magnetic stirring in ethyl ether) with different TiCl ₄ concentrations were compared in order to obtain optimum dehydrogenation properties of LiAlH ₄. At 80 °C, TiCl ₄-doped LiAlH ₄ can release up to 6.5 wt.%-H ₂, which opens the way to use of exhaust heat of PEM fuel cells to trigger the hydrogen release from LiAlH ₄. Highlights: LiAlH ₄ was doped with TiCl ₄ using three different doping techniques. Optimum dehydrogenation properties were found testing various TiCl ₄ concentrations. TiCl ₄-doped LiAlH4 can release up to 6.5 wt.% hydrogen. Dehydrogenation kinetics of TiCl ₄-doped LiAlH ₄ was studied systematically at 80 °C.