Fluorite-structured Mg-based Hydrogen Storage Materials:A Challenging Route towards the Future Hydrogen Economy

摘要

1.Introduction It has been identified that hydrogen storage is one of the key drivers, enabling the future hydrogen economy. High-energy density materials will play a dominant role in future gas phase and electrochemical devices, such as Fuel Cells and rechargeable NiMH batteries. Significantly higher gravimetric storage capacities are, however, required to accomplish the necessary breakthroughs. It has recently been shown that more than 6.5 wt.% of hydrogen can be electrochemically absorbed and desorbed at high rates at room temperature in fluorite-structured Mg-compounds [1-3]. It has been argued that, in contrast to the well-known rutile-structured Mg-alloys these materials have a much more open crystal structure, facilitating fast hydrogen transport[4]. In this contribution the electrochemical [1-4] and crystallographic[5,6] aspects of this new class of hydride-forming materials will be addressed. Apart from the storage capacity, one of the most important characteristics is the absorption/desorption isotherm. Both a thermodynamic and kinetic modelling approach will be presented, allowing to accurate simulate these complex (de)hydrogenation processes[7-9].