Thermodynamics and dynamics of the Mg–Fe–H system and its potential for thermochemical thermal energy storage

• Published in: Journal of alloys and compounds 2002-10, Vol.345 (1), p.77-89
• Main Authors: Bogdanović, Borislav, Reiser, Alexander, Schlichte, Klaus, Spliethoff, Bernd, Tesche, Bernd
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electron, ion, and scanning probe microscopy; Energy accumulation; Energy storage systems, including capacitor banks; Exact sciences and technology; Mg 2FeH 6; Physics; Statistical physics, thermodynamics, and nonlinear dynamical systems; Structure of solids and liquids; crystallography; Thermal energy density; Thermal energy storage; Thermodynamic functions and equations of state; Thermodynamics; Thermodynamics and dynamics; Transmission electron microscopy; Transmission, reflection and scanning electron microscopy(including ebic)
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(02)00308-0

The reversible Mg 2FeH 6 and the mixed Mg 2FeH 6–MgH 2 hydride systems [ Eqs. (1) and (2)] turned out to be highly suitable materials for thermochemical thermal energy storage at around 500 °C, for example as the storage of solar or excess industrial heat. The systems are characterized by a high gravimetric and volumetric thermal energy density in comparison to sensible or latent heat storage materials ( Table 1) and have excellent stability in cycle tests. Further advantages include low price of the starting materials, a free choice and constancy of the heat delivery temperature by controlling the applied hydrogen pressure, and the absence of heat losses with time. By means of combined TEM–EDX investigations essential features of the initial formation and the subsequent de- and rehydrogenation processes of Mg 2FeH 6 could be elucidated on a micro- or nanoscale level.