Thermodynamics and performance of the Mg-H-F system for thermochemical energy storage applications
dc.contributor.author | Tortoza, Mariana | |
dc.contributor.author | Humphries, Terry | |
dc.contributor.author | Sheppard, Drew | |
dc.contributor.author | Paskevicius, Mark | |
dc.contributor.author | Rowles, Matthew | |
dc.contributor.author | Sofianos, M. Veronica | |
dc.contributor.author | Aguey-Zinsou, K | |
dc.contributor.author | Buckley, Craig | |
dc.date.accessioned | 2018-02-19T07:59:21Z | |
dc.date.available | 2018-02-19T07:59:21Z | |
dc.date.created | 2018-02-19T07:13:31Z | |
dc.date.issued | 2018 | |
dc.identifier.citation | Tortoza, M. and Humphries, T. and Sheppard, D. and Paskevicius, M. and Rowles, M. and Sofianos, M. and Aguey-Zinsou, K. et al. 2018. Thermodynamics and performance of the Mg-H-F system for thermochemical energy storage applications. Physical Chemistry Chemical Physics. 20 (4): pp. 2274-2283. | |
dc.identifier.uri | http://hdl.handle.net/20.500.11937/65723 | |
dc.identifier.doi | 10.1039/c7cp07433f | |
dc.description.abstract |
© 2018 the Owner Societies. Magnesium hydride (MgH 2 ) is a hydrogen storage material that operates at temperatures above 300 °C. Unfortunately, magnesium sintering occurs above 420 °C, inhibiting its application as a thermal energy storage material. In this study, the substitution of fluorine for hydrogen in MgH 2 to form a range of Mg(H x F 1-x ) 2 (x = 1, 0.95, 0.85, 0.70, 0.50, 0) composites has been utilised to thermodynamically stabilise the material, so it can be used as a thermochemical energy storage material that can replace molten salts in concentrating solar thermal plants. These materials have been studied by in situ synchrotron X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, temperature-programmed-desorption mass spectrometry and Pressure-Composition-Isothermal (PCI) analysis. Thermal analysis has determined that the thermal stability of Mg-H-F solid solutions increases proportionally with fluorine content, with Mg(H 0.85 F 0.15 ) 2 having a maximum rate of H 2 desorption at 434 °C, with a practical hydrogen capacity of 4.6 ± 0.2 wt% H 2 (theoretical 5.4 wt% H 2 ). An extremely stable Mg(H 0.43 F 0.57 ) 2 phase is formed upon the decomposition of each Mg-H-F composition of which the remaining H 2 is not released until above 505 °C. PCI measurements of Mg(H 0.85 F 0.15 ) 2 have determined the enthalpy (?H des ) to be 73.6 ± 0.2 kJ mol -1 H 2 and entropy (?S des ) to be 131.2 ± 0.2 J K -1 mol -1 H 2 , which is slightly lower than MgH 2 with ?H des of 74.06 kJ mol -1 H 2 and ?S des = 133.4 J K -1 mol -1 H 2 . Cycling studies of Mg(H 0.85 F 0.15 ) 2 over six absorption/desorption cycles between 425 and 480 °C show an increased usable cycling temperature of ~80 °C compared to bulk MgH 2 , increasing the thermal operating temperatures for technological applications. | |
dc.publisher | R S C Publications | |
dc.relation.sponsoredby | http://purl.org/au-research/grants/arc/LP120101848 | |
dc.relation.sponsoredby | http://purl.org/au-research/grants/arc/LP150100730 | |
dc.relation.sponsoredby | http://purl.org/au-research/grants/arc/LE0775551 | |
dc.relation.sponsoredby | http://purl.org/au-research/grants/arc/FT160100303 | |
dc.title | Thermodynamics and performance of the Mg-H-F system for thermochemical energy storage applications | |
dc.type | Journal Article | |
dcterms.source.volume | 20 | |
dcterms.source.number | 4 | |
dcterms.source.startPage | 2274 | |
dcterms.source.endPage | 2283 | |
dcterms.source.issn | 1463-9076 | |
dcterms.source.title | Physical Chemistry Chemical Physics | |
curtin.department | School of Electrical Engineering, Computing and Mathematical Science (EECMS) | |
curtin.accessStatus | Open access | |
curtin.contributor.orcid | Sofianos, M. Veronica [0000-0002-9654-1463] | |
curtin.contributor.orcid | Rowles, Matthew [0000-0002-7448-6774] | |
curtin.contributor.orcid | Paskevicius, Mark [0000-0003-2677-3434] | |
curtin.contributor.orcid | Humphries, Terry [0000-0003-2677-3434] | |
curtin.contributor.orcid | Tortoza, Mariana [0000-0003-2677-3434] | |
curtin.contributor.orcid | Buckley, Craig [0000-0002-3075-1863] |