(5r) A Computational Study of the Role of Carbon in the Hydrogen Storage Kinetics of Lithium Beryllium Hydrides | AIChE

(5r) A Computational Study of the Role of Carbon in the Hydrogen Storage Kinetics of Lithium Beryllium Hydrides



The problems involved in the storage of hydrogen are one of the main barriers for the practical usage of Proton Exchange Membrane (PEM) fuel cells in automobile applications. There are many approaches of storing hydrogen which are being explored, but none of them have been able to satisfy all the US DOE's requirements. Metal Hydrides are one of those alternatives being researched upon. While many metal hydrides are reported to be capable of meeting the gravimetric and the volumetric storage densities, favorable kinetics and thermodynamics (dehydrogenation of these metal hydrides at the room temperature) is one thing that needs to be resolved to be able to make these materials available for hydrogen storage. Lithium Beryllium Hydrides (LiBeH3) [J. Alloys and Compounds vol 307 pg 157] are a group of hydrides which have been recently proposed as having a reversible hydrogen storage capacity of more than 8 wt%. Anyways it was reported that this hydride required to be heated up to a temperature of 150oC for the desorption of hydrogen, which is beyond the requirements. Magnesium Hydride is another class of hydrides which need to be heated upto 250 to 300oC for the dehydrogenation

It is also reported elsewhere [Mat. Sci. Engg. B vol 108 pg 24] that there is a remarkable improvement in absorption/desorption kinetics of the metal hydride (like MgH2) when it is ball milled with graphite/carbon. It is expected that a small amount of carbon present in the LiBeH3 might also lower its dehydrogenation temperature to the room temperature. Density Functional Theory calculations will be used to further characterize the role of carbon in the desorption kinetics of Lithium beryllium hydride LiBeH3. A detailed analysis of the possible crystal structure of this compound will be performed using Molecular Dynamics.