Sorption behavior of the MgH2–Mg2FeH6 hydride storage system synthesized by mechanical milling followed by sintering

Puszkiel, Julián; Gennari, F.C.; Larochette, P. Arneodo; Karimi, Fahim; Pistidda, Claudio; Gosalawit–Utke, Rapee; Jepsen, Julian; Gundlach, Carsten; Colbe, José M. Bellosta von; Klassen, Thomas; Dornheim, Martin

doi:10.1016/j.ijhydene.2013.08.068

Cited by 40 publications

(21 citation statements)

References 47 publications

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“…Some authors reported that Mg 2 FeH 6 is formed from the metallic elements [2,4,19,24], while others claimed that MgH 2 is the Mg 2 FeH 6 precursor [9,20,21,25,26]. Recently, we studied the transformation of phases during hydrogen absorption of a ball milled 2Mg + Fe mixture [27].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Effect of Milling Atmosphere and Starting Composition on Mg2FeH6 Formation

Asselli

Huot

2014

Metals

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Abstract:In this study we investigated the synthesis and the hydrogen storage properties of Mg 2 FeH 6 . The complex hydride was prepared by ball milling under argon and hydrogen atmosphere from 2Mg + Fe and 2MgH 2 + Fe compositions. The samples were characterized by X-ray powder diffraction and scanning electron microcopy. Kinetics of hydrogen absorption and desorption were measured in a Sievert's apparatus. We found that the milling atmosphere plays a more important role on Mg 2 FeH 6 synthesis than the starting compositions. Ball milling under hydrogen pressure resulted in smaller particles sizes and doubled the yield of Mg 2 FeH 6 formation. Despite the microstructural differences after ball milling, all samples had similar hydrogen absorption and desorption kinetics. Loss of capacity was observed after only five cycles of hydrogen absorption/desorption.

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Section: Introductionmentioning

confidence: 99%

Investigation of Effect of Milling Atmosphere and Starting Composition on Mg2FeH6 Formation

Asselli

Huot

2014

Metals

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“…We also showed that the synthesis efficiency can be improved to more than 95% for the direct reaction from a MgH 2 and Fe mixture using the appropriate processing parameters [12]. The reaction between magnesium hydride and iron was also studied in depth by Puszkiel et al [13]. The authors carefully described the mechanisms of Mg 2 FeH 6 formation and decomposition and proved that, in the MgH 2 -MgFe system, synergistic destabilizing effects occur, improving the decomposition and formation reaction rates.…”

Section: Introductionmentioning

confidence: 80%

Mg2FeH6 Synthesis Efficiency Map

et al. 2018

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Abstract:The influences of the processing parameters on the Mg 2 FeH 6 synthesis yield were studied. Mixtures of magnesium hydride (MgH 2 ) and iron (Fe) were mechanically milled in a planetary ball mill under argon for 0.5-, 1-, 2-and 3-h periods and subsequently sintered at temperatures from 300-500 • C under hydrogen. The reaction yield, phase content and hydrogen storage properties of the received materials were investigated. The morphologies of the powders after synthesis were studied by SEM. The synthesis effectiveness map was presented. The obtained results prove that synthesis parameters, such as the milling time and synthesis temperature, greatly influence the reaction yield and material properties and show that extended mechanical milling may not be beneficial to the reaction efficiency.

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“…This growth process provided a characteristic vermicular form for the initially formed Mg 2 FeH 6 particles, which was kept even after hundreds of hydrogenation-dehydrogenation cycles [1]. Later investigations on the hydrogenation mechanism of Mg-Fe-H system, carried out under dynamic conditions, showed that the formation of Mg 2 FeH 6 occurs via two consecutive reactions [9][10][11][12]. Mg 2 FeH 6 was synthesized from stoichiometric mixture of 2Mg:Fe powder by reactive mechanical milling in hydrogen atmosphere via the intermediate formation of MgH 2 , undergoing the simultaneous formation of MgH 2 and Mg 2 FeH 6 [9].…”

Section: Introductionmentioning

confidence: 94%

“…Mg 2 FeH 6 was synthesized from stoichiometric mixture of 2Mg:Fe powder by reactive mechanical milling in hydrogen atmosphere via the intermediate formation of MgH 2 , undergoing the simultaneous formation of MgH 2 and Mg 2 FeH 6 [9]. Puszkiel et al [11] found by in situ XRD experiments under 50 bar H 2 that MgH 2 is first formed at 215 • C from free Mg. Then, MgH 2 reacts with Fe to form Mg 2 FeH 6 at 350 • C. The complete formation of Mg 2 FeH 6 complex hydride is constrained at low temperature, due to kinetic restrictions related to solid-solid diffusion processes. The formation of MgH 2 from 2Mg:Fe is kinetically favored at temperatures around 200 • C. At higher temperatures, the solid-solid diffusion processes are enhanced, hence, Mg 2 FeH 6 is formed from MgH 2 and Fe.…”

Section: Introductionmentioning

confidence: 99%

New Insight on the Hydrogen Absorption Evolution of the Mg–Fe–H System under Equilibrium Conditions

Puszkiel

Riglos

Ramallo‐López

et al. 2018

Metals

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Mg2FeH6 is regarded as potential hydrogen and thermochemical storage medium due to its high volumetric hydrogen (150 kg/m3) and energy (0.49 kWh/L) densities. In this work, the mechanism of formation of Mg2FeH6 under equilibrium conditions is thoroughly investigated applying volumetric measurements, X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), and the combination of scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS) and high-resolution transmission electron microscopy (HR-TEM). Starting from a 2Mg:Fe stoichiometric powder ratio, thorough characterizations of samples taken at different states upon hydrogenation under equilibrium conditions confirm that the formation mechanism of Mg2FeH6 occurs from elemental Mg and Fe by columnar nucleation of the complex hydride at boundaries of the Fe seeds. The formation of MgH2 is enhanced by the presence of Fe. However, MgH2 does not take part as intermediate for the formation of Mg2FeH6 and acts as solid-solid diffusion barrier which hinders the complete formation of Mg2FeH6. This work provides novel insight about the formation mechanism of Mg2FeH6.

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Sorption behavior of the MgH2–Mg2FeH6 hydride storage system synthesized by mechanical milling followed by sintering

Cited by 40 publications

References 47 publications

Investigation of Effect of Milling Atmosphere and Starting Composition on Mg2FeH6 Formation

Investigation of Effect of Milling Atmosphere and Starting Composition on Mg2FeH6 Formation

Mg2FeH6 Synthesis Efficiency Map

New Insight on the Hydrogen Absorption Evolution of the Mg–Fe–H System under Equilibrium Conditions

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