A Review of Recent Advances on the Effects of Microstructural Refinement and Nano-Catalytic Additives on the Hydrogen Storage Properties of Metal and Complex Hydrides

Abstract

Abstract:The recent advances on the effects of microstructural refinement and various nano-catalytic additives on the hydrogen storage properties of metal and complex hydrides obtained in the last few years in the allied laboratories at the University of Waterloo (Canada) and Military University of Technology (Warsaw, Poland) are critically reviewed in this paper. The research results indicate that microstructural refinement (particle and grain size) induced by ball milling influences quite modestly the hydrogen storage properties of simple metal and complex metal hydrides. On the other hand, the addition of nanometric elemental metals acting as potent catalysts and/or metal halide catalytic precursors brings about profound improvements in the hydrogen absorption/desorption kinetics for simple metal and complex metal hydrides alike. In general, catalytic precursors react with the hydride matrix forming a metal salt and free nanometric or amorphous elemental metals/intermetallics which, in turn, act catalytically. However, these catalysts change only kinetic properties i.e. the hydrogen absorption/desorption rate but they do not change thermodynamics (e.g., enthalpy change of hydrogen sorption reactions). It is shown that a complex metal hydride, LiAlH 4 , after high energy ball milling with a nanometric Ni metal catalyst and/or MnCl 2 catalytic precursor, is able to desorb relatively large quantities of hydrogen at RT, 40 and 80 °C . This kind of behavior is very encouraging for the future development of solid state hydrogen systems. OPEN ACCESSEnergies 2011, 4 2 Keywords: solid state hydrogen storage; ball milling; microstructural refinement; particle/grain size; nano-catalytic additives; simple metal and complex hydrides

A Revisit to the Hydrogen Desorption/Absorption Behaviors of LiAlH4/LiBH4: Effects of Catalysts

“…In addition, 1 mol % TiCl 3 -2LiAlH 4 +LiBH 4 provides the highest amount of hydrogen desorption among the doped samples, 6.4 wt %. A possible reason is the fact that TiCl 3 could facilitate the crystallite size reduction of the hydride during the milling process resulting in the hydrogen storage improvement [13]. However, the hydrogen desorption capacities of all the doped mixtures are significantly lower than that of the undoped one.…”

Review of magnesium hydride-based materials: development and optimisation

“…Nanostructuring by mechanochemical synthesis [8] introduces defects into the material which can enhance the kinetic rates, particularly for diffusion of hydrogen. Additives including transition metals, oxides and halides as well as carbons and others have also been found to significantly improve the reaction kinetics [9,10]. Attempts to modify the thermodynamic properties of MgH 2 [11] have not been as successful.…”

Mechanism and kinetics of early transition metal hydrides, oxides, and chlorides to enhance hydrogen release and uptake properties of MgH2

“…Nanonickel (n-Ni) is well established as efficient catalyst for the Mg/MgH 2 system, which acts via the intermediate Mg 2 NiH 4 Varin et al, 2009Varin et al, , 2011Pasquini et al, 2011;Callini et al, 2013). Other metals, e.g., Al, Ti, Cu, Pd may have both a thermodynamic and kinetic effect by forming magnesium containing alloys (Andreasen et al, 2005Callini et al, 2010).…”

“…Obstacles to its widespread use are the high decomposition temperature (∼300°C) and the slow kinetics of hydrogen absorption-desorption. Traditionally, the solution to these problems is found in nanostructuring that can be achieved, for example, by mechano-chemical treatment (Huot et al, 1999;Paskevicius et al, 2010), use of effective catalysts (Schimmel et al, 2005;Varin et al, 2011) or by introducing of additives that alter the thermodynamic properties of the system (Jin et al, 2007a;Cuevas et al, 2012). Nanosized metals may have lower melting point or spontaneous alloying as compared with their bulk form (Hirokazu and Kitagawa, 2012).…”