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High temperature metal hydrides as heat storage materials for solar and related applications.

Felderhoff M, Bogdanović B - Int J Mol Sci (2009)

Bottom Line: High temperature metal hydrides offer high heat storage capacities around this temperature.Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability.Relevant properties of these hydrides and their possible applications as heat storage materials are described.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck Institut für Kohlenforschung, Mülheim/Ruhr, Germany. felderhoff@mpi-muelheim.mpg.de <felderhoff@mpi-muelheim.mpg.de>

ABSTRACT
For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 degrees C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

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1000 cycle test of Ni-doped MgH2, time for a full cycle 3 h.
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f2-ijms-10-00325: 1000 cycle test of Ni-doped MgH2, time for a full cycle 3 h.

Mentions: At the beginning of our research work on metal hydrides there was the experimental finding that the reaction of magnesium with hydrogen in solution can be catalyzed [7]. During the past years the research in this field has led to MgH2/Mg materials which fulfill the above mentioned criteria: satisfactory kinetics combined with stability upon cyclic hydrogen charging and discharging. The first method for the preparation of the so-called “active MgH2/Mg materials” (Equation 3) [1, 8] consists in treatment of commercial Mg powder (f.i. 270 mesh) with hydrogen in an organic solvent (i.e. toluene) in the presence of a small amount of the soluble organometallic nickel complex bis(cyclooctadiene-1,5-Ni(0) [9] at ambient temperature and normal pressure. The Ni-complex is hereby instantaneously hydrogenated to cyclooctane and metallic nickel and the latter, in a fine dispersion, is precipitated on the surface of the Mg particles and acts as a catalyst for hydrogenation and dehydrogenation of the former. The second method [8] consists of intimately mixing of the Mg powder with 4–10 wt.% of fine commercial Ni powder. The activity of the material prepared according to the second method is somewhat lower than that of the first method. Cycle stability of the “standard materials” is presented in Ref. [8] (Figures 4, 5 and 9 therein). The Mg powders doped with Ni in these ways and fabricated several times on a 10 kg scale were shown in numerous tests to be suitable materials for heat and hydrogen storage and were employed by us and by others in several storage installation prototypes [1, 8, 10–12], three of which are presented in Section 3. Already after the first hydrogenation the materials are fully active and remain active during hundreds of hydrogen charging-discharging cycles. A more recent 1,000 cycle test using both materials is shown in Figure 2 [13]. Some restrictions at high temperatures are discussed further in Section 4.


High temperature metal hydrides as heat storage materials for solar and related applications.

Felderhoff M, Bogdanović B - Int J Mol Sci (2009)

1000 cycle test of Ni-doped MgH2, time for a full cycle 3 h.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2662468&req=5

f2-ijms-10-00325: 1000 cycle test of Ni-doped MgH2, time for a full cycle 3 h.
Mentions: At the beginning of our research work on metal hydrides there was the experimental finding that the reaction of magnesium with hydrogen in solution can be catalyzed [7]. During the past years the research in this field has led to MgH2/Mg materials which fulfill the above mentioned criteria: satisfactory kinetics combined with stability upon cyclic hydrogen charging and discharging. The first method for the preparation of the so-called “active MgH2/Mg materials” (Equation 3) [1, 8] consists in treatment of commercial Mg powder (f.i. 270 mesh) with hydrogen in an organic solvent (i.e. toluene) in the presence of a small amount of the soluble organometallic nickel complex bis(cyclooctadiene-1,5-Ni(0) [9] at ambient temperature and normal pressure. The Ni-complex is hereby instantaneously hydrogenated to cyclooctane and metallic nickel and the latter, in a fine dispersion, is precipitated on the surface of the Mg particles and acts as a catalyst for hydrogenation and dehydrogenation of the former. The second method [8] consists of intimately mixing of the Mg powder with 4–10 wt.% of fine commercial Ni powder. The activity of the material prepared according to the second method is somewhat lower than that of the first method. Cycle stability of the “standard materials” is presented in Ref. [8] (Figures 4, 5 and 9 therein). The Mg powders doped with Ni in these ways and fabricated several times on a 10 kg scale were shown in numerous tests to be suitable materials for heat and hydrogen storage and were employed by us and by others in several storage installation prototypes [1, 8, 10–12], three of which are presented in Section 3. Already after the first hydrogenation the materials are fully active and remain active during hundreds of hydrogen charging-discharging cycles. A more recent 1,000 cycle test using both materials is shown in Figure 2 [13]. Some restrictions at high temperatures are discussed further in Section 4.

Bottom Line: High temperature metal hydrides offer high heat storage capacities around this temperature.Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability.Relevant properties of these hydrides and their possible applications as heat storage materials are described.

View Article: PubMed Central - PubMed

Affiliation: Max-Planck Institut für Kohlenforschung, Mülheim/Ruhr, Germany. felderhoff@mpi-muelheim.mpg.de <felderhoff@mpi-muelheim.mpg.de>

ABSTRACT
For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 degrees C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

Show MeSH
Related in: MedlinePlus