Exploring halide destabilised calcium hydride as a high-temperature thermal battery

JOURNAL OF ALLOYS AND COMPOUNDS

卷:819

Article

Sofianos, M. Veronica¹  Randall, Samuel¹  Paskevicius, Mark¹  Aguey-Zinsou, Kondo-Francois²  Rowles, Matthew R.³  Humphries, Terry D.¹  Buckley, Craig E.¹ 

[1] Curtin Univ, Fuels & Energy Technol Inst, GPO Box U1987, Perth, WA 6845, Australia

[2] Univ New South Wales, Sch Chem Engn, MERLin Grp, Sydney, NSW 2052, Australia

[3] Curtin Univ, John de Laeter Ctr, GPO Box U1987, Perth, WA 6845, Australia

关键词: Calcium hydride;    Destabilisation;    Thermochemical heat storage;    Concentrated solar power;   

DOI  :  10.1016/j.jallcom.2019.153340

来源: Elsevier

【 摘 要 】

CaH2 is a metal hydride with a high energy density that decomposes around 1100 degrees C at 1 bar of H-2 pressure. Due to this high decomposition temperature, it is difficult to utilise this material as a thermal battery for the next generation of concentrated solar power plants, where the currently targeted operational temperature is between 600 and 800 degrees C. In this study, CaH2 has been mixed with calcium halide salts (CaCl2, CaBr2 and Cal(2)) and annealed at 450 degrees C under 100 bar of H-2 pressure to form CaHCI, CaHBr and CaHI. These hydride-halide salts incur a thermodynamic destabilisation of their hydrogen release, compared to CaH2, so that they can operate between 600 and 800 degrees C within practical operating pressures (1-10 bar H-2) for thermochemical energy storage. The as-synthesised metal hydrides were studied by in-situ synchrotron X-ray diffraction, temperature programmed desorption and pseudo pressure composition isothermal analysis. Each of the calcium hydride-halide salts decomposed to form calcium metal and a calcium halide salt after hydrogen release. In comparison to pure CaH2, their decomposition reactions were faster when heated up to 850 degrees C, and the experimental values of the desorbed hydrogen gas were very close to the theoretical ones. All samples after their decomposition showed signs of sintering, which hindered their rehydrogenation reaction. (C) 2019 Elsevier B.V. All rights reserved.

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