Influence of cycling on the thermodynamic and structure properties of nanocrystalline magnesium based hydride

Dehouche, Zahir; Djaozandry, R; Huot, Jacques; Boily, S.; Goyette, J.; Bose, T. K.; Schulz, Robert

doi:10.1016/s0925-8388(00)00718-0

Cited by 85 publications

(38 citation statements)

References 13 publications

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“…Consequently, the fast kinetics obtained for nanocrystalline microstructures is generally explained by their large grain boundary area, which facilitates fast diffusion of hydrogen within MgH 2 particles, and which provides a high number of nucleation sites for the phase transformation. [10,12,21,22] The annealing experiments performed by Huhn et al show that coarsening above a certain threshold crystallite size > 80 nm leads to a slow-down in reaction kinetics, [13] which is attributed to the hydride shell formation and the increasing volume within the crystallites that can only be filled at a slow rate.…”

Section: Discussionmentioning

confidence: 99%

Tailoring Hydrogen Storage Materials Towards Application

Dornheim¹,

Eigen²,

et al. 2006

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A breakthrough in hydrogen storage technology was achieved by preparing nanocrystalline hydrides using high‐energy ball milling and the use of suitable catalysts/additives. These new materials show fast or in case of Mg‐based hydrides very fast absorption and desorption kinetics within minutes, thus qualifying lightweight Mg‐ or Al‐based hydrides for storage applications. This article summarizes our current understanding of the kinetics of Mg‐based light metal hydrides, describes an approach for a cost‐effective processing technology and highlights some promising new developments in lightweight metal hydride research.

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Section: Discussionmentioning

confidence: 99%

Tailoring Hydrogen Storage Materials Towards Application

Dornheim¹,

Eigen²,

et al. 2006

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“…Other reasons for the reduction in cycle life are: impurities in the hydrogen gas leading to poisoning [127][128][129][130][131], agglomeration of particles [132], structural relaxation and crystalline growth [133], phase change and/ or formation of non-hydride phases [134,135]. Nevertheless, magnesium and magnesium-based compounds could sustain up to a few thousand cycles without drastic changes in hydrogen sorption properties [133,[136][137][138]. A special way to improve cycling stability is by element substitution [139][140][141][142][143][144][145].…”

Section: Cycle Lifementioning

confidence: 99%

Metal Hydrides

Huot

2010

Handbook of Hydrogen Storage

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Metal hydrides are promising candidates for many stationary and mobile hydrogen storage applications. Presently, the most common use of metal hydrides is as anode material in commercial nickel-metal hydrides (Ni-MH) rechargeable batteries which have replaced conventional nickel-cadmium batteries in many applications. A wide variety of Ni-MH batteries are now on the market with cell sizes ranging from 30 mAh to 250 Ah [1,2]. Some other applications are: hydrogen compression [3], aircraft fire-detectors [4], isotope separation [5], and hydrogen getters for microelectronic packages. Hydride formation is also used in the HDDR process (hydrogenation-disproportionation-desorption-recombination) for the synthesis of magnetic materials such as Nd 2 Fe 14 B [6]. A striking application is as a component of cryocoolers for the ESA Planck mission [7]. Another exciting new application is the use of metal hydrides for switchable mirrors [8]. As we can see, metal hydrides have a wide range of applications. However, most research and development is targeted towards two applications: batteries and hydrogen storage. The former is now widely exploited but the latter is still facing many technical problems. The main advantages of storing hydrogen in a metal hydride are the high hydrogen volumetric densities (sometimes higher than in liquid hydrogen) and the possibility to absorb and desorb hydrogen with a small change in hydrogen pressure [9].The physics of hydrogen in elemental metals was reviewed at the end of the 1970s in thebooksHydrogeninMetals,volumesIandII [10,11].The1970s alsosawtheemergence of the important field of intermetallic compounds as hydride materials. An in-depth review of this field can be found in Hydrogen in Intermetallic Compounds volumes I, and II [12,13]. A review of the propertiesand applications of hydrogen in metals can befound in the third volume of Hydrogen in Metals [14]. The basic properties of the metal-hydrogen system are discussed from a fundamental point of view by Fukai [15]. Although initial studies on nanocrystalline and amorphous metal hydrides were initiated around the 1980s [16], the real emergence of nanocrystalline metal hydrides as a new class of Handbook of Hydrogen Storage. Edited by Michael Hirscher

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“…Moreover, in contrast to some intermetallic compounds, which show significant degradation against cycling [2], the binary metal hydride systems exhibit good resistance against repeated desorption-absorption phase transformations [3,4]. On the other hand, these sorption reactions are quite slow so that high temperatures are required for fast hydrogen absorption and release.…”

Section: Introductionmentioning

confidence: 99%

Microstructural and Kinetic Evolution of Fe Doped MgH2 during H2 Cycling

et al. 2012

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The effect of extended H 2 sorption cycles on the structure and on the hydrogen storage performances of MgH 2 powders with 5 wt% of Fe particle catalyst is reported. MgH 2 powders with and without Fe have been ball milled under Argon, the doped MgH 2 nanocomposite has been cycled under hydrogen pressure up to a maximum of 47 desorption and absorption cycles at 300 °C. After acceleration during the first 10 cycles, the kinetics behavior of doped MgH 2 is constant after extended cycling, in terms of maximum storage capacity and rate of sorption. The major effect of cycling on particle morphology is the progressive extraction of Mg from the MgO shell surrounding the powder particles. The Mg extraction from the MgO shell leaves the catalyst particles inside the hydride particles. Many empty MgO shells are observed in the pure ball milled MgH 2 upon cycling at higher temperature, suggesting that this enhancement of the extraction efficiency is related to the higher operating temperature which favors Mg diffusivity with respect to the H ion one.

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Influence of cycling on the thermodynamic and structure properties of nanocrystalline magnesium based hydride

Cited by 85 publications

References 13 publications

Tailoring Hydrogen Storage Materials Towards Application

Tailoring Hydrogen Storage Materials Towards Application

Metal Hydrides

Microstructural and Kinetic Evolution of Fe Doped MgH2 during H2 Cycling

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