Evaluation of the enthalpy change due to hydrogen desorption for M–N–H (M = Li, Mg, Ca) systems by differential scanning calorimetry

Tokoyoda, Kazuhiko; Ichikawa, Takayuki; Miyaoka, Hiroki

doi:10.1016/j.ijhydene.2014.11.086

Cited by 11 publications

(3 citation statements)

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“…Mg(NH 2 ) 2 used in this work was synthesized by the method reported before [ 15 , 25 ]. Mg(NH 2 ) 2 and 10 h milled LiH were mixed with a 3:8 molar ratio by ball-milling for 2 and 20 h, and the property of each mixture was compared with the samples synthesized from the pristine LiH (see also Figure S1 ).…”

Section: Resultsmentioning

confidence: 99%

“…The reaction of typical Li system is described as follows [ 12 ]: LiH + LiNH 2 ↔ Li 2 NH + H 2 in this system, lithium amide (LiNH 2 ) phase in the hydrogenated state is changed to imide phase (Li 2 NH) after the hydrogen desorption. Although about 6.0 mass% of hydrogen is reversibly stored, the hydrogen desorption requires more than 200 °C due to the high enthalpy change, Δ H = 67 kJ·mol −1 H 2 [ 13 , 14 , 15 ]. To decrease the reaction temperature, the lithium hydride (LiH) and magnesium amide (Mg(NH 2 ) 2 ) system has been proposed.…”

Section: Introductionmentioning

confidence: 99%

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Kinetic Modification on Hydrogen Desorption of Lithium Hydride and Magnesium Amide System

et al. 2015

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Various synthesis and rehydrogenation processes of lithium hydride (LiH) and magnesium amide (Mg(NH2)2) system with 8:3 molar ratio are investigated to understand the kinetic factors and effectively utilize the essential hydrogen desorption properties. For the hydrogen desorption with a solid-solid reaction, it is expected that the kinetic properties become worse by the sintering and phase separation. In fact, it is experimentally found that the low crystalline size and the close contact of LiH and Mg(NH2)2 lead to the fast hydrogen desorption. To preserve the potential hydrogen desorption properties, thermochemical and mechanochemical rehydrogenation processes are investigated. Although the only thermochemical process results in slowing the reaction rate due to the crystallization, the ball-milling can recover the original hydrogen desorption properties. Furthermore, the mechanochemical process at 150 °C is useful as the rehydrogenation technique to preserve the suitable crystalline size and mixing state of the reactants. As a result, it is demonstrated that the 8LiH and 3Mg(NH2)2 system is recognized as the potential hydrogen storage material to desorb more than 5.5 mass% of H2 at 150 °C.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetic Modification on Hydrogen Desorption of Lithium Hydride and Magnesium Amide System

et al. 2015

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“…The versatility of the DSC is vast and researchers apply it to assess: coal,() cjceass,() waste,() catalysts,() minerals,() cement,() ceramics,() alloys,() and polymers. () Applications include: gasification,() pyrolysis,() combustion,() adsorption,() desorption,() calcination,() dehydration,() thermal stability,() phase transitions,() phase diagrams,() polymer crystallization,() glass transition, curing time, and reaction kinetics …”

Section: Applicationsmentioning

confidence: 99%

Experimental methods in chemical engineering: Differential scanning calorimetry—DSC

et al. 2018

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Differential calorimetry assesses energy flow between a sample and its environment. The sample may be heated at a known heating rate (either constant or temperature modulated), or held in an isothermal environment or adiabatic environment depending on instrument and experimental design. The subset of differential calorimetry that deals with known heating or cooling rates is termed differential scanning calorimetry (DSC) and is a foundational technique to modern thermodynamics. It reports the heat flow versus temperature or time from which we calculate specific heat capacity at constant pressure, c P , enthalpy of fusion, and the heat of reaction. Moreover, it identifies how microstuctural properties evolve and thermal arrests-a characteristic of phase transitions. Heat-flux DSCs measure the temperature difference between a reference and a sample that sit on a thin two-dimensional plate. Power compensated DSCs heat reference material and the sample in independent furnaces while maintaining each at the same temperature. The Tian-Calvet DSC is similar to the heat-flux DSC, but minimizes error induced at high temperature with ring shaped thermopiles that surround the reference and the sample and in most designs incorporate the independent furnaces characteristic of heat flux DSC (three-dimensional heat flow probe). Convection and radiation energy leaks compromise accuracy above 600 • C, particularly for pan-style heat flux and power-compensated DSC, which are sensitive to heat transfer by conduction only. The Tian-Calvet DSC maximizes the signal-to-noise ratio by enveloping the sample and reference in the thermopile. Web of Science indexed 11 800 articles in 2016 and 2017 that mentioned DSC and assigned 789 to chemical engineering, which ranks it 5th after polymer science, material science, physical chemistry, and multi-disciplinary chemistry. A bibliometric analysis recognizes four research clusters: polymers and nano-composites, alloys and kinetics, nano-particles and drug delivery, and fibres.

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Improved hydrogen storage properties of combined Ca(BH4)2 and LiBH4 system motivated by addition of LaMg3 assisted with ball milling in H2

Gao

Wen

et al. 2015

International Journal of Hydrogen Energy

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Evaluation of the enthalpy change due to hydrogen desorption for M–N–H (M = Li, Mg, Ca) systems by differential scanning calorimetry

Cited by 11 publications

References 43 publications

Kinetic Modification on Hydrogen Desorption of Lithium Hydride and Magnesium Amide System

Kinetic Modification on Hydrogen Desorption of Lithium Hydride and Magnesium Amide System

Experimental methods in chemical engineering: Differential scanning calorimetry—DSC

Improved hydrogen storage properties of combined Ca(BH4)2 and LiBH4 system motivated by addition of LaMg3 assisted with ball milling in H2

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