Significantly improved dehydrogenation of LiBH4 destabilized by TiF3

The hydrogen storage properties of LiBH4 ball milled with TiF3 were investigated. It was found that the LiBH4-TiF3 mixture exhibited significantly improved dehydrogenation properties. For example, the LiBH4-TiF3 (mole ratio: 3 : 1) sample started to release hydrogen at around 100 degrees C, and the hydrogen desorption capacity reached 5.0 wt% at 250 degrees C. Furthermore, the dehydrogenated product can be partially rehydrogenated at 100 atm H-2 and 350 degrees C. X-Ray diffraction (XRD), infrared (IR) spectroscopy and X-ray photoelectron spectroscopy (XPS) characterizations revealed that the decreased dehydrogenation conditions in the LiBH4-TiF3 system resulted from an exothermic reaction of 3LiBH(4) + TiF3 -> 3LiF + TiB2 + B + 6H(2), which improved both its thermodynamics and kinetics. As the above reaction is exothermic, the reverse reaction is not feasible, further investigations indicated that the rehydrogenation may be due to the formation of another borohydride.