Atomic-scale processes in materials for solid-state hydrogen storage.
Zbigniew Łodziana
Zbigniew.lodziana@empa.ch
EMPA, Hydrogen & Energy, Überlandstrasse 129, CH-8600 Dübendorf
Switzerland and
IFJ, Polish Academy of Sciences, ul. Radzikowskiego 152, Krakow, Poland
At present wealthy of the societies are based mainly on fossil fuels. Their limited
resources induced growing interest in the research toward economy based a clean and
highly abundant energy carriers, like hydrogen. Hydrogen storage in safe and compact
way is one of the most demanding obstacles for widespread introduction of this fuel. The
target goals for the hydrogen storage were defined in so called freedom car vision, where
hydrogen storage capacity of weight 10.8% is expected in 2015. Solid-state hydrogen
storage in so-called complex hydrides is considered as the most promising solution of
hydrogen storage problem.
Complex hydrides are known for more then a half of the century, however many
of their physicochemical properties are still uncovered. This is a consequence of
experimental difficulties in studies of light element compounds and problematic synthesis
methods of complex hydrides.
In the presentation we show interrelation of modern neutron and X-ray diffraction
and theoretical methods that can lead to insight into atomic structure of complex hydrides
at high temperatures. As an example we discuss atomic motion in LiBH4 and structure of
Ca(BH4)2 and Mg(BH4)2.
For the practical applications of complex hydrides for hydrogen storage
knowledge of kinetic processes in these materials seems to be crucial. Here theoretical
methods provide detailed insight into processes of defect formation or hydrogen
diffusion. Example of titanium catalyst applied for sodium alanate and lithium
borohydride will be discussed.
Present status for complex hydrides, as materials for hydrogen storage, open
questions and challenges will be discussed.