Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures
© the Owner Societies. CaH2 has 20 times the energy density of molten salts and was patented in 2010 as a potential solar thermal energy storage material. Unfortunately, its high operating temperature (>1000 °C) and corrosivity at that temperature make it challenging to use as a thermal energ...
| Main Authors: | , , , , |
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| Format: | Journal Article |
| Language: | English |
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ROYAL SOC CHEMISTRY
2020
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| Online Access: | http://purl.org/au-research/grants/arc/LE0775551 http://hdl.handle.net/20.500.11937/82259 |
| _version_ | 1848764487966916608 |
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| author | Balakrishnan, Sruthy Sofianos, M. Veronica Humphries, Terry Paskevicius, Mark Buckley, Craig |
| author_facet | Balakrishnan, Sruthy Sofianos, M. Veronica Humphries, Terry Paskevicius, Mark Buckley, Craig |
| author_sort | Balakrishnan, Sruthy |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | © the Owner Societies.
CaH2 has 20 times the energy density of molten salts and was patented in 2010 as a potential solar thermal energy storage material. Unfortunately, its high operating temperature (>1000 °C) and corrosivity at that temperature make it challenging to use as a thermal energy storage (TES) material in concentrating solar power (CSP) plants. To overcome these practical limitations, here we propose the thermodynamic destabilization of CaH2 with Zn metal. It is a unique approach that reduces the decomposition temperature of pure CaH2 (1100 °C at 1 bar of H2 pressure) to 597 °C at 1 bar of H2 pressure. Its new decomposition temperature is closer to the required target temperature range for TES materials used in proposed third-generation high-temperature CSP plants. A three-step dehydrogenation reaction between CaH2 and Zn (1 : 3 molar ratio) was identified from mass spectrometry, temperature-programmed desorption and in situ X-ray diffraction studies. Three reaction products, CaZn13, CaZn11 and CaZn5, were confirmed from in situ X-ray diffraction studies at 190 °C, 390 °C and 590 °C, respectively. The experimental enthalpy and entropy of the second hydrogen release reaction were determined by pressure composition isotherm measurements, conducted between 565 and 614 °C, as ΔHdes = 131 ± 4 kJ mol-1 H2 and ΔSdes = 151 ± 4 J K-1 mol-1 H2. Hydrogen cycling studies of CaZn11 at 580 °C showed sufficient cycling capacity with no significant sintering occurring during heating, as confirmed by scanning electron microscopy, demonstrating its great potential as a TES material for CSP applications. Finally, a cost comparison study of known destabilized CaH2 systems was carried out to assess the commercial potential. |
| first_indexed | 2025-11-14T11:20:09Z |
| format | Journal Article |
| id | curtin-20.500.11937-82259 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:20:09Z |
| publishDate | 2020 |
| publisher | ROYAL SOC CHEMISTRY |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-822592021-11-08T02:46:50Z Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures Balakrishnan, Sruthy Sofianos, M. Veronica Humphries, Terry Paskevicius, Mark Buckley, Craig Science & Technology Physical Sciences Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics X-RAY-DIFFRACTION THERMODYNAMIC PROPERTIES HYDROGEN STORAGE METAL-HYDRIDES © the Owner Societies. CaH2 has 20 times the energy density of molten salts and was patented in 2010 as a potential solar thermal energy storage material. Unfortunately, its high operating temperature (>1000 °C) and corrosivity at that temperature make it challenging to use as a thermal energy storage (TES) material in concentrating solar power (CSP) plants. To overcome these practical limitations, here we propose the thermodynamic destabilization of CaH2 with Zn metal. It is a unique approach that reduces the decomposition temperature of pure CaH2 (1100 °C at 1 bar of H2 pressure) to 597 °C at 1 bar of H2 pressure. Its new decomposition temperature is closer to the required target temperature range for TES materials used in proposed third-generation high-temperature CSP plants. A three-step dehydrogenation reaction between CaH2 and Zn (1 : 3 molar ratio) was identified from mass spectrometry, temperature-programmed desorption and in situ X-ray diffraction studies. Three reaction products, CaZn13, CaZn11 and CaZn5, were confirmed from in situ X-ray diffraction studies at 190 °C, 390 °C and 590 °C, respectively. The experimental enthalpy and entropy of the second hydrogen release reaction were determined by pressure composition isotherm measurements, conducted between 565 and 614 °C, as ΔHdes = 131 ± 4 kJ mol-1 H2 and ΔSdes = 151 ± 4 J K-1 mol-1 H2. Hydrogen cycling studies of CaZn11 at 580 °C showed sufficient cycling capacity with no significant sintering occurring during heating, as confirmed by scanning electron microscopy, demonstrating its great potential as a TES material for CSP applications. Finally, a cost comparison study of known destabilized CaH2 systems was carried out to assess the commercial potential. 2020 Journal Article http://hdl.handle.net/20.500.11937/82259 10.1039/d0cp04431h English http://purl.org/au-research/grants/arc/LE0775551 http://purl.org/au-research/grants/arc/LP150100730 http://purl.org/au-research/grants/arc/LE0989180 http://purl.org/au-research/grants/arc/FT160100303 http://purl.org/au-research/grants/arc/LE170100199 ROYAL SOC CHEMISTRY fulltext |
| spellingShingle | Science & Technology Physical Sciences Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics X-RAY-DIFFRACTION THERMODYNAMIC PROPERTIES HYDROGEN STORAGE METAL-HYDRIDES Balakrishnan, Sruthy Sofianos, M. Veronica Humphries, Terry Paskevicius, Mark Buckley, Craig Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| title | Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| title_full | Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| title_fullStr | Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| title_full_unstemmed | Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| title_short | Thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| title_sort | thermochemical energy storage performance of zinc destabilized calcium hydride at high-temperatures |
| topic | Science & Technology Physical Sciences Chemistry, Physical Physics, Atomic, Molecular & Chemical Chemistry Physics X-RAY-DIFFRACTION THERMODYNAMIC PROPERTIES HYDROGEN STORAGE METAL-HYDRIDES |
| url | http://purl.org/au-research/grants/arc/LE0775551 http://purl.org/au-research/grants/arc/LE0775551 http://purl.org/au-research/grants/arc/LE0775551 http://purl.org/au-research/grants/arc/LE0775551 http://purl.org/au-research/grants/arc/LE0775551 http://hdl.handle.net/20.500.11937/82259 |