ChemInform Abstract: Thermodynamics of Hydrogen Desorption from NaMgH₃ and Its Application as a Solar Heat Storage Medium.

Abstract

Thermodynamics of Hydrogen Desorption from NaMgH 3 and Its Application as a Solar Heat Storage Medium. -NaMgH3 is synthesized by cryomilling (77 K) of NaH and MgH2 followed by annealing at 300°C under 50 bar H2. Its thermodynamic properties and hysteresis are determined by kinetic desorption measurements for each data point of the pressure-composition isotherms. Both the decomposition enthalpy and entropy are lower than previously reported. Complete hydrogen desorption to metallic Na and Mg results in macroscopic segregation that kinetically hinders rehydrogenation to NaMgH3. Provided decomposition to Na metal is avoided, NaMgH3 is a potential solar heat storage material. -(SHEPPARD*, D. A.; PASKEVICIUS, M.; BUCKLEY, C. E.; Chem.

Solar Receiver with Integrated Thermal Storage for a Supercritical Carbon Dioxide Power Cycle

“…Recently, Sheppard et al [17] assessed the performance of the perovskite-type hydride, NaMgH3 under high temperature CSP plant conditions. The authors suggest the use of NaMgH3 hydride at temperatures between 580-600 °C; however, material cycling stability and other issues have limited the current potential for this material.…”

Metal hydrides for thermochemical energy storage applications

“…One more category of Mg‐based complex hydride is perovskite‐type hydride (NaMgH 3 ) that follows a two‐step decomposition process (Equations , , and ) and releases a total of 6.0 wt% of H 2 . The NaMgH 3 materials possess high thermal stability and relatively low cost, making them a potential candidate for solar thermal storage 81 …”

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