Heat capacity and thermodynamic properties of alkali and alkali-earth borohydrides. (April 2020)

• Record Type: Journal Article
• Authors: Dematteis, Erika M.; Jensen, Steffen R.; Jensen, Torben R.; Baricco, Marcello
• Is Part Of: Journal of chemical thermodynamics. Volume 143(2020)
• Publication Date: 2020-04
• Subjects: Complex hydrides -- Borohydride -- Heat capacity -- Thermodynamics -- Hydrogen storage; Thermodynamics -- Periodicals; Thermochemistry -- Periodicals; Thermodynamique -- Périodiques; Thermochimie -- Périodiques; Thermochemistry; Thermodynamics; Periodicals; 541.369
• DOI: 10.1016/j.jct.2020.106055
• Languages: English
• ISSNs: 0021-9614

Abstract

Highlights: The above room temperature heat capacity, Cp, for Na, K, Rb, Cs, Mg, Ca borohydrides has been measured by DSC as a function of temperature. The measured Cp values have been compared with available extrapolated literature data, and they have been modelled as a function of temperature according to the Calphad method. The variations of Cp values for different polymorphs were studied in details and related to the corresponding crystal structures, considering the mobility of the BH4 - group. From the whole set of assessed thermodynamic data, possible correlations with dynamics and structural properties have been estimated. Abstract: In this work, the above room temperature heat capacity for different polymorphs of alkali and alkali-earth ( i.e. Na, K, Rb, Cs, Mg, Ca) borohydrides has been measured by DSC as a function of temperature. The above room temperature measured Cp values have been compared with available extrapolated literature data, and they have been modelled as a function of temperature according to the Calphad method. The variations of Cp values for different polymorphs were studied in details and they have been related to the corresponding crystal structures, considering the mobility of the BH4 − group. From the whole set of assessed thermodynamic data, possible correlations with dynamics and structural properties have been estimated.