In Situ NMR Study on the Interaction between LiBH4–Ca(BH4)2 and Mesoporous Scaffolds

Lee, Hyun‐Sook; Hwang, Son‐Jong; Kim, Hoon Kee; Lee, Young-Su; Park, Jinsol; Yu, Jong‐Sung; Cho, Young Whan

doi:10.1021/jz301199y

Cited by 24 publications

(22 citation statements)

References 32 publications

(82 reference statements)

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“…Decomposition of LiMg and LiCa eutectics occur above 250 °C and 350 °C respectively . The nanoconfinement improved these reactions lowering the hydrogen release temperature to 150 °C and 200 °C respectively …”

Section: Introductionsupporting

confidence: 73%

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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Section: Introductionsupporting

confidence: 73%

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

et al. 2019

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“…Interestingly, the room temperature conductivity of LiBH 4 can be dramatically increased to 10 –4 S cm –1 by infiltrating it into mesoporous scaffolds or mixing with nanoparticles. , Such infiltrated LiBH 4 was employed as an electrolyte in the all-solid-state electrochemical cell . The enhanced Li ion diffusion at the interface with C, SiO 2 , or Al 2 O 3 has been demonstrated, mostly by NMR spectroscopy, ,− but its atomistic origin is still illusive. Unless the crystal structure of o -LiBH 4 is completely destroyed at the interface, we may be able to interpret the increased interface conductivity in terms of the defect structure of o -LiBH 4 .…”

Section: Introductionmentioning

confidence: 99%

Fast Lithium Ion Migration in Room Temperature LiBH₄

Lee

Cho

2017

J. Phys. Chem. C

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The defect structure and the Li ion diffusion mechanism of orthorhombic LiBH4 (o-LiBH4) are studied by first-principles calculations to elucidate the Li ion transport in o-LiBH4. Two metastable Li interstitial sites are identified, and the formation energies of the Schottky and Frenkel defect pair are calculated to be 1.2–1.4 eV, the former being slightly easier to form. The energy required to form intrinsic defects is higher than that of hexagonal LiBH4 (h-LiBH4). On the other hand, the migration energy barrier of the Li vacancy or interstitial ranges from 0.1 to 0.3 eV, which is comparable to that of h-LiBH4. Therefore, the higher defect formation energy mainly accounts for the much lower Li ion conductivity of o-LiBH4. The calculated overall activation barrier for the Li ion conduction is in fair agreement with the experimental activation energy. Molecular dynamics simulation demonstrates that both the interstitial and the interstitialcy mechanisms are operative for the Li interstitial diffusion and that the interconnected interstitial sites compose a fast diffusion path. The simulation results point out that the enhancement of the carrier density via defect or interface engineering may significantly raise the ionic conductivity of o-LiBH4.

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“…Multiple binary metal borohydride systems based on LiBH 4 and various other hydrides such as NaBH 4 , KBH 4 , Mg(BH 4 ) 2 , − Ca(BH 4 ) 2 , ,− LiAlH 4 , and NaAlH 4 , have been nanoconfined and reported in the literature. The combination of two relatively stable metal borohydrides may facilitate mutual decomposition and eutectic melting properties. , Most of these nanoconfined metal borohydride systems display improved hydrogen release kinetics and increasing stability of hydrogen storage capacity over several cycles.…”

Section: Introductionmentioning

confidence: 99%

Reversibility of LiBH₄ Facilitated by the LiBH₄–Ca(BH₄)₂ Eutectic

Javadian

Payandeh

et al. 2017

J. Phys. Chem. C

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The hydrogen storage properties of eutectic melting 0.68LiBH4–0.32Ca(BH4)2 (LiCa) as bulk and nanoconfined into a high surface area, S BET = 2421 ± 189 m2/g, carbon aerogel scaffold, with an average pore size of 13 nm and pore volume of V tot = 2.46 ± 0.46 mL/g, is investigated. Hydrogen desorption and absorption data were collected in the temperature range of RT to 500 °C (ΔT/Δt = 5 °C/min) with the temperature then kept constant at 500 °C for 10 h at hydrogen pressures in the range of 1–8 and 134–144 bar, respectively. The difference in the maximum H2 release rate temperature, T max, between bulk and nanoconfined LiCa during the second cycle is ΔT max ≈ 40 °C, which over five cycles becomes smaller, ΔT max ≈ 10 °C. The high temperature, T max ≈ 455 °C, explains the need for high temperatures for rehydrogenation in order to obtain sufficiently fast reaction kinetics. This work also reveals that nanoconfinement has little effect on the later cycles and that nanoconfinement of pure LiBH4 has a strong effect in only the first cycle of H2 release. The hydrogen storage capacity is stable for bulk and nanoconfined LiCa in the second to the fifth cycle, which contrasts to nanoconfined LiBH4 where the H2 storage capacity continuously decreases. Bulk and nanoconfined LiCa have hydrogen storage capacities of 5.4 and 3.7 wt % H2 in the fifth H2 release, which compare well with the calculated hydrogen contents of LiBH4 only and in LiCa, which are 5.43 and 3.69 wt % H2, respectively. Thus, decomposition products of Ca(BH4)2 appear to facilitate the full reversibility of the LiBH4, and this approach may lead to new hydrogen storage systems with stable energy storage capacity over multiple cycles of hydrogen release and uptake.

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In Situ NMR Study on the Interaction between LiBH₄–Ca(BH₄)₂ and Mesoporous Scaffolds

Cited by 24 publications

References 32 publications

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

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

Fast Lithium Ion Migration in Room Temperature LiBH₄

Reversibility of LiBH₄ Facilitated by the LiBH₄–Ca(BH₄)₂ Eutectic

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In Situ NMR Study on the Interaction between LiBH4–Ca(BH4)2 and Mesoporous Scaffolds

Cited by 24 publications

References 32 publications

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

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

Fast Lithium Ion Migration in Room Temperature LiBH4

Reversibility of LiBH4 Facilitated by the LiBH4–Ca(BH4)2 Eutectic

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Product

Resources

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In Situ NMR Study on the Interaction between LiBH₄–Ca(BH₄)₂ and Mesoporous Scaffolds

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

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

Fast Lithium Ion Migration in Room Temperature LiBH₄

Reversibility of LiBH₄ Facilitated by the LiBH₄–Ca(BH₄)₂ Eutectic