Nanocrystalline magnesium for hydrogen storage

Załuska, A.; Załuski, L.; Ström‐Olsen, J. O.

doi:10.1016/s0925-8388(99)00073-0

Cited by 1,098 publications

(672 citation statements)

References 26 publications

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“…It also allows the activation procedure (which is generally required prior to the first absorption reaction) to be suppressed. However, results published elsewhere [17], [19] and [20] using MgH 2 as a starting material are always slightly better than our results. Some experiments are underway on the MgH 2 -Co mixture submitted to RMG.…”

Section: Resultscontrasting

confidence: 64%

“…This relationship does not exist for the MG product suggesting two different behaviors. To a first approximation, we could conclude that the driving force of diffusion in the case of MG product is the intragrain diffusion as shown by Zaluska et al [19] as in the case of the RMG product the intergrain diffusion should not be considered as negligible.…”

Section: Hydriding Propertiesmentioning

confidence: 83%

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Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture

Bobet

Chevalier

Darriet

2002

Journal of Alloys and Compounds

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:Reactive mechanical grinding (MG under H 2 ) of magnesium powder improves the hydrogen sorption properties. The hydrogenation of Mg starts in situ during the milling process that allows suppressing the activation procedure generally requested for Mg. The addition of Co, which acts as a catalyst for the dissociation of H 2 , also leads to an improvement of the hydrogen sorption properties (but a strong dependence upon the milling time is reported). The hydriding is determined to be a two-step process: nucleation and diffusion. A direct relationship exists between the nucleation duration and the specific surface. A critical milling time exists below which the diffusion process is improved and above which no more improvement is observed (the maximum internal stress in the powder is also reached at this critical time). The diffusion is controlled by the number of crystallites per particle which can be decreased by increasing the milling time up to 10 h. However, the sorption properties of Mg-Co mixtures are a little under those reported for MgH 2 -metal mixtures.

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Section: Resultscontrasting

confidence: 64%

Section: Hydriding Propertiesmentioning

confidence: 83%

Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture

Bobet

Chevalier

Darriet

2002

Journal of Alloys and Compounds

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“…Our results are consistent with those found by Vajeeston and co-workers. 28 Furthermore, ReaxFF MgH calculates a heat of formation of -20.00 kcal/mol for the R-MgH 2 phase, which is in good 6,9,30 To determine whether a further reduction of grain size below the 20 nm regime could sufficiently destabilize the MgH 2 nanoparticles, we have investigated the enthalpy of formation of ultrasmall MgH 2 particles below the 20 nm regime.…”

Section: Reaction Energiesmentioning

confidence: 99%

“…b With zeropoint vibration for H2 (ZPE for MgH2 not included, although incorporation of the ZPE for MgH2 will raise the energy of ∆H and improve the agreement with DFT results). (6) and corresponding structures are given in Figure 11. The rdf(s) indicates two types of hydrogen corresponding to the peaks, centered at 1.7 Å (type I) and 2.3 Å (type II).…”

Section: Figurementioning

confidence: 99%

“…Hence, it is necessary to decrease the desorption temperature to obtain a suitable hydrogen storage material. Numerous methods have been focused on improving the problematic sorption kinetic, including mechanical ball milling 4,5,6 and mechanical alloying. 7,8 However, these methods can only improve adsorption and not desorption kinetics, 9 possibly because even the smallest particle sizes obtainable by these methods (20 nm) still primarily display bulk desorption characteristics.…”

Section: Introductionmentioning

confidence: 99%

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ReaxFF_MgH Reactive Force Field for Magnesium Hydride Systems

et al. 2005

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We have developed a reactive force field (ReaxFF MgH ) for magnesium and magnesium hydride systems. The parameters for this force field were derived from fitting to quantum chemical (QM) data on magnesium clusters and on the equations of states for condensed phases of magnesium metal and magnesium hydride crystal. The force field reproduces the QM-derived cell parameters, density, and the equations of state for various pure Mg and MgH 2 crystal phases as well as and bond dissociation, angle bending, charge distribution, and reaction energy data for small magnesium hydride clusters. To demonstrate one application of ReaxFF MgH , we have carried out MD simulations on the hydrogen absorption/desorption process in magnesium hydrides, focusing particularly on the size effect of MgH 2 nanoparticles on H 2 desorption kinetics. Our results show a clear relationship between grain size and heat of formation of MgH 2 ; as the particle size decreases, the heat of formation increases. Between 0.6 and 2.0 nm, the heat of formation ranges from -16 to -19 kcal/Mg and diverges toward that of the bulk value (-20.00 kcal/Mg) as the particle diameter increases beyond 2 nm. Therefore, it is not surprising to find that Mg nanoparticles formed by ball milling (20-100 nm) do not exhibit any significant change in thermochemical properties.

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Magnesium

Amundsen

Aune

Bakke

et al. 2003

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. Properties 3. Raw Materials 4. Production 4.1. Extraction by Electrolysis 4.1.1. Preparation of Magnesium Chloride Cell Feed 4.1.1.1. Chlorination of Magnesia and Magnesite 4.1.1.2. Dehydration of Aqueous Magnesium Chloride Solutions 4.1.1.3. Dehydration of Carnallite 4.1.2. Electrolysis 4.1.2.1. Technical Data 4.1.2.2. Electrolytic Cells 4.2. Thermic Reduction Processes 4.3. Refining and Casting 4.4. Particulate Magnesium 5. Environmental Aspects 6. Quality Specifications 7. Uses 8. Economic Aspects 9. Toxicology and Occupational Health 10. Safety

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Nanocrystalline magnesium for hydrogen storage

Cited by 1,098 publications

References 26 publications

Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture

Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture

ReaxFF_MgH Reactive Force Field for Magnesium Hydride Systems

Magnesium

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Nanocrystalline magnesium for hydrogen storage

Cited by 1,098 publications

References 26 publications

Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture

Effect of reactive mechanical grinding on chemical and hydrogen sorption properties of the Mg+10 wt.% Co mixture

ReaxFFMgH Reactive Force Field for Magnesium Hydride Systems

Magnesium

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ReaxFF_MgH Reactive Force Field for Magnesium Hydride Systems