Hydrogen Storage Properties of Nanosized MgH2-0.1TiH2 Prepared by Ultrahigh-energy-high-pressure Milling

Journal Article · Thu Jul 29 04:00:00 EDT 2010 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/ja906340u· OSTI ID:972521

Lu, Jun; Choi, Young Joon; Fang, Zhigang Zak; Sohn, Hong Yong; Ronnebro, Ewa

Magnesium hydride (MgH2) is an attractive candidate for solid state hydrogen storage applications. To improve the kinetics and thermodynamic properties of MgH2 during dehydrogenation-rehydrogenation cycles, a nano-structured MgH2-0.1TiH2 material system prepared by ultrahigh-energy-high-pressure mechanical milling was investigated. High-resolution TEM and scanning TEM analysis showed that the grain size of the milled MgH2-0.1TiH2 powder is approximately 5-10 nm with uniform distributions of TiH2 among MgH2 particles. Pressure-Composition-Temperature (PCT) analysis demonstrated that both the nanosize and the addition of TiH2 contributed to the significant improvement of the kinetics of dehydrogenation and hydrogenation compared to commercial MgH2. More importantly, PCT cycle analysis demonstrated that the MgH2-0.1TiH2 material system showed excellent cycle stability which is attributed to the inhibition of coarsening by TiH2. The results also showed that the ΔH value for the dehydrogenation of nanostructured MgH2-0.1TiH2 is significantly lower than that of commercial MgH2. However, the ΔS value of the reaction was also lower which results in minimum net effects of the nanosize and the addition of TiH2 on the equilibrium pressure of dehydrogenation reaction of MgH2.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 972521
• Report Number(s): PNNL-SA-67552; EB4202000
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 43 Vol. 131; ISSN 1932-7447
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

08 HYDROGEN
DEHYDROGENATION
GRAIN SIZE
HYDROGEN STORAGE
HYDROGENATION
Hydrogen storage materials
KINETICS
MAGNESIUM HYDRIDES
MILLING
STABILITY
THERMODYNAMIC PROPERTIES