Melting Behavior and Thermolysis of NaBH4−Mg(BH4)2 and NaBH4−Ca(BH4)2 Composites

Ley, Morten B.; Roedern, Elsa; Thygesen, Peter

doi:10.3390/en8042701

Cited by 25 publications

(11 citation statements)

References 48 publications

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“…200°C in a relatively wide composition range 0.6 \ x \ 0.8 [71]. 4 all displayed melting behaviour below that of the monometallic phases (up to 167°C lower) [70][71][72][73][74]. Generally, each system can behave differently with respect to their physical behaviours upon melting.…”

Section: Eutectic Melting Complex Hydridesmentioning

confidence: 99%

Complex and liquid hydrides for energy storage

et al. 2016

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The research on complex hydrides for hydrogen storage was initiated by the discovery of Ti as a hydrogen sorption catalyst in NaAlH 4 by Boris Bogdanovic in 1996. A large number of new complex hydride materials in various forms and combinations have been synthesized and characterized, and the knowledge regarding the properties of complex hydrides and the synthesis methods has grown enormously since then. A significant portion of the research groups active in the field of complex hydrides is collaborators in the International Energy Agreement Task 32. This paper reports about the important issues in the field of complex hydride research, i.e. the synthesis of borohydrides, the thermodynamics of complex hydrides, the effects of size and confinement, the hydrogen sorption mechanism and the complex hydride composites as well as the properties of liquid complex hydrides. This paper is the result of the collaboration of several groups and is an excellent summary of the recent achievements.

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Section: Eutectic Melting Complex Hydridesmentioning

confidence: 99%

Complex and liquid hydrides for energy storage

et al. 2016

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“…This peak was usually better observed during cooling, so that the onset liquidus temperature could be evaluated. 14,15,51 Selected pictures from TPPA for s2, s3, s6 and s7 are shown in Figure 2. The area of DSC peak corresponding to the eutectic melting is also at the maximum for this composition (data reported in ESI, Table S2 and Figure S2), confirming the occurrence of eutectic melting.…”

Section: Eutectic Melting Of Libh 4 -Nabhmentioning

confidence: 99%

A thermodynamic investigation of the LiBH₄–NaBH₄ system

et al. 2016

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The LiBH 4 -NaBH 4 pseudo-binary system has been investigated by X-ray diffraction, temperatureprogrammed photographic analysis, and differential scanning calorimetry, in order to establish the phase diagram. The polymorphic orthorhombic-to-hexagonal phase transition of LiBH 4 was observed at 94 °C in samples containing NaBH 4 , i.e. 15 °C lower than for pure LiBH 4 , which indicates the dissolution of sodium into LiBH 4 . The formation of solid solutions was confirmed by powder X-ray diffraction measurements performed as a function of temperature. A new eutectic composition between Li 0.65 Na 0.35 BH 4 and Li 0.70 Na 0.30 BH 4 , with a melting temperature of 216 °C, is observed. Ab-initio calculations have been performed to establish the relative stabilities of the pure compounds in orthorhombic, hexagonal and cubic structure. The obtained experimental and calculated data were compared with available literature values and they were used for a thermodynamic assessment of the LiBH 4 -NaBH 4 system by the Calphad method. The enthalpy of mixing for solid and liquid solutions has been estimated on the basis of experimental data.The LiBH4-NaBH4 pseudo-binary system has been investigated by X-ray diffraction, temperature programmed photographic analysis and differential scanning calorimetry, in order to establish the phase diagram. Ab-initio calculations have been performed to establish the relative stabilities of the pure compounds in various structures. The obtained experimental and calculated data were compared with available literature values and they were used for a thermodynamic assessment of the LiBH4-NaBH4 system by the Calphad method.

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“…Many eutectics are formed at a different molar fraction composition, from a temperature as low as 105 °C for 0.725LiBH 4 ‐0.275KBH 4 ,, 216 °C for 0.70LiBH 4 ‐0.30NaBH 4 ,, 150 °C for 0.55LiBH 4 ‐0.45Mg(BH 4 ) 2 , and 200 °C for 0.68LiBH 4 ‐0.32Ca(BH 4 ) 2 ,. In binary combinations without LiBH 4 , thermal minima or partial melting have been observed, at 462 °C for 0.682NaBH 4 ‐0.328KBH 4 , 205 °C for 0.40NaBH 4 ‐0.60Mg(BH 4 ) 2 , and above 350 °C for the NaBH 4 ‐Ca(BH 4 ) 2 system . The formation of solid solutions is limited to the NaBH 4 ‐KBH 4 and LiBH 4 ‐NaBH 4 systems.…”

Section: Introductionmentioning

confidence: 99%

Exploring Ternary and Quaternary Mixtures in the LiBH₄‐NaBH₄‐KBH₄‐Mg(BH₄)₂‐Ca(BH₄)₂ System

et al. 2019

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Binary combinations of borohydrides have been extensivly investigated evidencing the formation of eutectics, bimetallic compounds or solid solutions. In this paper, the investigation has been extended to ternary and quaternary systems in the LiBH 4 -NaBH 4 -KBH 4 -Mg(BH 4 ) 2 -Ca(BH 4 ) 2 system. Possible interactions among borohydrides in equimolar composition has been explored by mechanochemical treatment. The obtained phases were analysed by X-ray diffraction and the thermal behaviour of the mixtures were analysed by HP-DSC and DTA, defining temperature of transitions and decomposition reactions. The release of hydrogen was detected by MS, showing the role of the presence of solid solutions and multi-cation compounds on the hydrogen desorption reactions. The presence of LiBH 4 generally promotes the release of H 2 at about 200°C, while KCa (BH 4 ) 3 promotes the release in a single-step reaction at higher temperatures.The explorative investigation has evidenced the formation of bi/tri-metallic compounds such as KCa(BH 4 ) 3 , LiKMg(BH 4 ) 4 and LiK(BH 4 ) 2 . The relative thermodynamic stabilities of these compounds have been discussed in the present study. Many new ternary eutectics have been observed with a melting temperature in the range from 100°C to 140°C, much lower than the melting temperature of parent binary eutectics. The hydrogen desorption occurs from the liquid phase, via complex multi-steps reactions but with no significant differences compared to the quinary equimolar mixture previously investigated.

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Melting Behavior and Thermolysis of NaBH4−Mg(BH4)2 and NaBH4−Ca(BH4)2 Composites

Cited by 25 publications

References 48 publications

Complex and liquid hydrides for energy storage

Complex and liquid hydrides for energy storage

A thermodynamic investigation of the LiBH₄–NaBH₄ system

Exploring Ternary and Quaternary Mixtures in the LiBH₄‐NaBH₄‐KBH₄‐Mg(BH₄)₂‐Ca(BH₄)₂ System

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Melting Behavior and Thermolysis of NaBH4−Mg(BH4)2 and NaBH4−Ca(BH4)2 Composites

Cited by 25 publications

References 48 publications

Complex and liquid hydrides for energy storage

Complex and liquid hydrides for energy storage

A thermodynamic investigation of the LiBH4–NaBH4 system

Exploring Ternary and Quaternary Mixtures in the LiBH4‐NaBH4‐KBH4‐Mg(BH4)2‐Ca(BH4)2 System

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A thermodynamic investigation of the LiBH₄–NaBH₄ system

Exploring Ternary and Quaternary Mixtures in the LiBH₄‐NaBH₄‐KBH₄‐Mg(BH₄)₂‐Ca(BH₄)₂ System