Effect of additives on the synthesis and reversibility of Ca(BH4)2

Rongeat, C.; D'Anna, Vincenza; Hagemann, Hans-Rudolf; Borgschulte, A.; Züttel, A.; Schultz, L.; Gutfleisch, O.

doi:10.1016/j.jallcom.2009.12.080

Scientific article

English

Effect of additives on the synthesis and reversibility of Ca(BH4)2

Contributors

Rongeat, C.; D'Anna, Vincenza; Hagemann, Hans-Rudolf; Borgschulte, A.; Züttel, A.; Schultz, L.; Gutfleisch, O.

Published in

Journal of alloys and compounds, vol. 493, no. 1-2, p. 281-287

Publication date

2010

Abstract

Metal borohydrides are potential materials for solid state hydrogen due to their high gravimetric and volumetric hydrogen densities. Among them, Ca(BH4)2 is particularly interesting because of the predicted suitable thermodynamic properties. In this work, we investigate a new synthesis route using high pressure reactive ball milling. Starting from CaH2 and CaB6 with a TiCl3 or TiF3 as additive, a reaction yield of 19% is obtained after 24 h milling at room temperature and 140 bar H2. The presence of Ca(BH4)2 is confirmed by the presence of the stretching mode of the [BH4]- group in the infrared spectra of the as-milled samples. Using in-situ XRD, we observe the recrystallisation of a poorly crystallised Ca(BH4)2 phase present after milling. The reversible decomposition/formation of Ca(BH4)2 is obtained with higher yield (57%) using higher temperature and TiF3 as additive but not with TiCl3 despite its similar electronic structure. The differences observed using different additives and the influence of the anion are discussed.

Keywords

Hydrogen storage
Calcium borohydride
Reactive ball milling
Raman and infrared spectroscopy

UNIGE affiliation entities

Faculté des sciences / Section de chimie et biochimie / Département de chimie physique

Citation (ISO format)

RONGEAT, C. et al. Effect of additives on the synthesis and reversibility of Ca(BH4)2. In: Journal of alloys and compounds, 2010, vol. 493, n° 1-2, p. 281–287. doi: 10.1016/j.jallcom.2009.12.080

Article (Published version)

Identifiers

PID : unige:6412
DOI : 10.1016/j.jallcom.2009.12.080

Journal ISSN

0925-8388

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22/01/2010 12:23:00

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22/01/2010 12:23:00

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14/03/2023 15:28:27

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14/03/2023 15:28:27

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29/10/2024 14:42:04

Effect of additives on the synthesis and reversibility of Ca(BH4)2

Contributors

Published in

Publication date

Abstract

Keywords

UNIGE affiliation entities

Citation (ISO format)

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Journal ISSN

Technical informations

Creation

First validation

Update

Status update

Last indexation