Hydrogen storage properties of the 2LiBH4+MgH2 reactive hydride composite doped with Ti additives and Al.

J. A. PUSZKIEL; F. C. GENNARI; J. ANDRADE GAMBOA; P. ARNEODO LAROCHETTE

Hawaii

Conferencia; American Crystallographic Association, Annual Meeting; 2013

American Crystallographic Association

The practical application of hydrogen as new energy vector presents severalproblems that have not been solved yet. One of the major constraints is thelack of a safe, compact and efficient way to store hydrogen, mainly formobile applications. Solid-hydrogen storage is one of the potentialsolutions. The reaction 2LiBH4 + MgH2 = MgB2 + 2LiH + 4H2 has interestingcharacteristics for hydrogen storage purposes. It has a properthermodynamic stability (DH = 40.5 kJ.mol-1 H2) which involves a reducedhydrogen desorption temperature (Tdesorption= 225 ºC at 1 bar). It also hasa high hydrogen storage capacity of 11.45 wt. % H2. Nonetheless,kinetic constraints preclude desorption temperatures below 400 ºC. Theformation of MgB2 is responsible for the reversibility of this reactivehydride composite (RHC). Therefore, by modifying the formation kinetic ofMgB2 and/or altering MgB2 itself, lower desorption temperature and animproved kinetic behavior of the RHC can be reached. For instance, theaddition of a Ti based additive noticeably enhances the kinetic behavior ofthe RHC, i.e. stable desorption kinetic in an extremely short time. In thepresent work, X-ray diffraction, thermal analyses and volumetrictechniques, among others, are used to investigate the effect of Ti basedadditives as well as the doping of MgB2 with Al on the kinetic behavior ofthis promising RHC.