In‐Situ and Real‐time Monitoring of Mechanochemical Preparation of Li2Mg(NH2BH3)4 and Na2Mg(NH2BH3)4 and Their Thermal Dehydrogenation

Biliškov, Nikola; Borgschulte, Andreas; Užarević, Krunoslav; Halász, Ivan; Lukin, Stipe; Milošević, Sanja; Milanović, Igor; Novaković, Jasmina Grbović

doi:10.1002/chem.201702665

Cited by 22 publications

(12 citation statements)

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“…Abe et al . showed that hydrogen absorption of palladium can effectively be improved by ion bombardment . They used low energy ions (30–350 keV) of H + , He + , N + i Ar + with the fluence range between 10 14 –10 17 ions/cm 2 .…”

Section: Experimental Approach To Destabilization Of Hydrogen‐storagementioning

confidence: 99%

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Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Novaković

Kurko

et al. 2019

ChemPhysChem

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This review deals with the destabilization methods for improvement of storage properties of metal hydrides. Both theoretical and experimental approaches were used to point out the influence of various types of defects on structure and stability of hydrides. As a case study, Mg, and Ni based hydrides has been investigated. Theoretical studies, mainly carried out within various implementations of DFT, are a powerful tool to study mostly MgH 2 based materials. By providing an insight on metalhydrogen bonding that governs both thermodynamics and hydrogen kinetics, they allow us to describe phenomena to which experimental methods have a limited access or do not have it at all: to follow the hydrogen sorption reaction on a specific metal surface and hydrogen induced phase transformations, to describe structure of phase boundaries or to explain the impact of defects or various additives on MgH 2 stability and hydrogen sorption kinetics. In several cases theoretical calculations reveal themselves as being able to predict new properties of materials, including the ways to modify Mg or MgH 2 that would lead to better characteristics in terms of hydrogen storage. The influence of ion irradiation and mechanical milling with and without additives has been discussed. Ion irradiation is the way to introduce a well-defined concentration of defects (Frankel pairs) at the surface and subsurface layers of a material. Defects at the surface play the main role in sorption reaction since they enhance the dissociation of hydrogen. On the other hand, ball-milling introduce defects through the entire sample volume, refine the structure and thus decrease the path for hydrogen diffusion. Two Severe Plastic Deformation techniques were used to better understand the hydrogenation/dehydrogenation kinetics of Mg-and Mg 2 Nibased alloys: Equal-Angular-Channel-Pressing and Fast-Forging. Successive ECAP passes leads to refinement of the microstructure of AZ31 ingots and to instalment therein of high densities of defects. Depending on mode, number and temperature of ECAP passes, the H-sorption kinetics have been improved satisfactorily without any additive for mass H-storage applications considering the relative speed of the shaping procedure. A qualitative understanding of the kinetic advanced principles has been built. Fast-Forging was used for a "quasiinstantaneous" synthesis of Mg/Mg 2 Ni-based composites. Hydrogenation of the as-received almost bi-phased materials remains rather slow as generally observed elsewhere, whatever are multiple and different techniques used to deliver the composite alloys. However, our preliminary results suggest that a synergic hydrogenation / dehydrogenation process should assist hydrogen transfers from Mg/Mg 2 Ni on one side to MgH 2 / Mg 2 NiH 4 on the other side via the rather stable a-Mg 2 NiH 0.3 , acting as in-situ catalyser.

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Section: Experimental Approach To Destabilization Of Hydrogen‐storagementioning

confidence: 99%

“…At the ambient temperature and pressure their capacities become very low. On the other hand, in aminoboranes,, borohydrides, and metal hydrides hydrogen is chemically bonded to the storage medium. Due to relatively high activation energy, the sorption in such kind of materials is usually not reversible.…”

Section: Introductionmentioning

confidence: 99%

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Novaković

Kurko

et al. 2019

ChemPhysChem

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“…Despite the important advantages mechanochemical activation offers in the area of hydrogen storage, the physico‐chemical mechanisms laying behind this phenomenon and in particular the associated tribological activation effects remained poorly understood. Recently, several experimental techniques have been developed, which allow for in situ and real‐time monitoring the mechanochemical transformations during milling that bridges the gap in the mechanistic understanding of these complex processes . Tribological activation correspond to the sliding of one surface against another .…”

Section: Non‐thermal and Non‐straightforward Thermally Driven Methodsmentioning

confidence: 99%

Unconventional Approaches to Hydrogen Sorption Reactions: Non‐Thermal and Non‐Straightforward Thermally Driven Methods

et al. 2019

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In the last decades, a broad family of hydrides have attracted attention as prospective hydrogen storage materials of very high gravimetric and volumetric capacity, fast H 2 -sorption kinetics, environmental friendliness and economical affordability. However, constraints due to their high activation energies of the different H 2 -sorption steps and the Gibbs energy of their reaction with H 2 has led to the need of high thermal energy to drive H 2 uptake and release. High heat leads to significant degradation effects (recrystallization, phase segregation, nanoparticles agglomeration…) of the hydrides. In this context, this short review aims to summarize alternative non-thermal methods and non-straightforward thermally driven methods to overcome the previous constraints. The phenomenology lying behind these methods, i. e. tribological activation, sonication, and electromagnetic radiation, and the effect of these processes on hydrogen sorption properties of hydrides are described. These non-usual approaches could boost the capability of the next generation of solid-hydride materials for hydrogen conversion in energy sector, in mobile devices and as hydrogen reservoirs.[a] J.

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“…Mechanical milling under diverse conditions (different type of mills [15][16][17], BPR [18][19][20], different milling atmospheres [21][22][23]) is widely used as a method to improve sorption kinetics of various hydrides [24][25][26][27][28] and mostly magnesium hydride MgH 2 [29][30][31][32][33]. Regarding MgH 2 , the most common way to improve sorption kinetics is mechanical milling with the addition of transition metals -TM (Nb, V, Ti, Mn, Fe, Co, Ni, Cu, Zn) [34][35][36][37] [38][39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

The influence of mechanical milling parameters on hydrogen desorption from Mgh2-Wo3 composites

Pantić

Milanović

Lukić

et al. 2020

International Journal of Hydrogen Energy

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The influence of different milling conditions obtained using two high-energy mills on hydrogen desorption from MgH 2 -WO 3 composites was investigated. The morphology, particle and crystallite size were studied as a function of milling speed, vial's volume, and ball-to-powder ratio. The vial's fill level, the number, and type of milling balls and additive's content kept constant. Changes in morphology and microstructure were correlated to desorption properties of materials. Higher milling speed reduced particle size but, there is no significant crystallite size reduction. On the other hand, additive distribution is similar regardless of the energy input. It has been noticed that different energy input on milling blend, which is the result of combined effects of above-mentioned factors, reflects on desorption temperature but not on the kinetics of desorption. In fact, desorption mechanism changes from 2D to 3D growth with constant nucleation rate, despite obtained changes in microstructure or chemical composition of the material.

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In‐Situ and Real‐time Monitoring of Mechanochemical Preparation of Li₂Mg(NH₂BH₃)₄ and Na₂Mg(NH₂BH₃)₄ and Their Thermal Dehydrogenation

Cited by 22 publications

References 50 publications

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Influence of Defects on the Stability and Hydrogen‐Sorption Behavior of Mg‐Based Hydrides

Unconventional Approaches to Hydrogen Sorption Reactions: Non‐Thermal and Non‐Straightforward Thermally Driven Methods

The influence of mechanical milling parameters on hydrogen desorption from Mgh2-Wo3 composites

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