Mechanochemistry of Metal Hydrides: Recent Advances

Abstract

This paper is a collection of selected contributions of the 1st International Workshop on Mechanochemistry of Metal Hydrides that was held in Oslo in May 2018. In this paper, the recent developments in the use of mechanochemistry to synthesize and modify metal hydrides are reviewed. A special emphasis is made on new techniques beside the traditional way of ball milling. High energy milling, ball milling under hydrogen reactive gas, cryomilling and severe plastic deformation techniques such as High-Pressure Torsion (HPT), Surface Mechanical Attrition Treatment (SMAT) and cold rolling are discussed. The new characterization method of in-situ X-ray diffraction during milling is described.

Synthesis of Nanostructured TiFe Hydrogen Storage Material by Mechanical Alloying via High‐Pressure Torsion

“…[24] However, the concentration of oxygen contamination and/or the level of oxidation is always more significant, when powders are processed by the HPT method. [32,68,69] In summary, this study together with earlier studies on the application of HPT for synthesis [54][55][56][57][58] or processing [49][50][51][52][53] of hydrogen storage materials confirm the potential of method for future developments in this field. As the addition of a third element to TiFe, such as Pd, [11] Ni, [12] Mn, [13][14][15][16] and Zr, [17][18][19] can facilitate the activation, synthesis of such ternary intermetallics by HPT can be considered as a potential future application.…”

“…To have a complete and uniform phase transformation, larger shear strains should be applied, as attempted earlier for other materials. [36][37][38][39][40][41][42][43][44][45][46][47][48][54][55][56][57][58] However, the main reason that larger shear strains were not applied in this study was due to the extremely high hardness of TiFe at large number of turns, which could make significant damage to the HPT anvils.…”

“…[34,35] The method was used successfully by the group of authors to synthesize various kinds of nanostructured intermetallics in different systems, such as Al-Ni, [36] Al-Ti, [37] Al-Cu, [38] Al-Ti-Ni, [39] Fe-Ni, [40] Mg-Ti, [41,42] Mg-Zr, [43] Mg-Hf, [44] Mg-Ni-Pd, [45] and Mg-V-Cr. [46] It is worth mentioning that, following publication of two articles in 2004 [47] and 2007, [48] the HPT process became popular not only for processing [49][50][51][52][53] but also for synthesizing [54][55][56][57][58] various kinds of hydrogen storage materials.…”

Hydrogen Sorption and Reversibility of the LiBH4-KBH4 Eutectic System Confined in a CMK-3 Type Carbon via Melt Infiltration

“…The bulk eutectic LiBH 4 -KBH 4 mixture (denoted hereafter as LiK) was prepared starting from LiBH 4 (95%, Sigma-Aldrich, St. Louis, MO, USA) and KBH 4 (97%, Sigma-Aldrich, St. Louis, MO, USA) in accordance with references [25,26] and with a molar ratio of LiBH 4 and KBH 4 equal to 0.725:0.275, obtaining a system with a melting temperature of 378 K. The two components were mixed first manually with a pestle and mortar and then mechanically, in order to obtain a system as homogeneous as possible. The mechanochemical treatment was performed with a planetary mill (PULVERISETTE 4, Fritsch GmbH, Idar-Oberstein, Germany) using a tungsten carbide jar with internal volume of 80 mL and 10 mm diameter spheres from the same material; the powder-to-balls weight ratio was 1:30 [42]. The milling process consisted of 5 min of milling at 400 rpm followed by 2 min of pause, in order to avoid the overheating and decomposition of the material during milling.…”

Magnesium-Based Materials for Hydrogen Storage—A Scope Review

“…Mechanochemical synthesis or milling allows the production of magnesium hydride with or without additives [ 18 , 76 ] by reactive ball milling (RBM), which is basically BM in a hydrogen atmosphere, or by simply BM in an inert atmosphere, respectively. These are the most common techniques used for the production of many metal hydrides.…”