Thermodynamic Properties and Reversible Hydrogenation of LiBH4–Mg2FeH6 Composite Materials
نویسندگان
چکیده
In previous studies, complex hydrides LiBH4 and Mg2FeH6 have been reported to undergo simultaneous dehydrogenation when ball-milled as composite materials (1 − x)LiBH4 + xMg2FeH6. The simultaneous hydrogen release led to a decrease of the dehydrogenation temperature by as much as 150 K when compared to that of LiBH4. It also led to the modified dehydrogenation properties of Mg2FeH6. The simultaneous dehydrogenation behavior between stoichiometric ratios of LiBH4 and Mg2FeH6 is not yet understood. Therefore, in the present work, we used the molar ratio x = 0.25, 0.5, and 0.75, and studied the isothermal dehydrogenation processes via pressure–composition–isothermal (PCT) measurements. The results indicated that the same stoichiometric reaction occurred in all of these composite materials, and x = 0.5 was the molar ratio between LiBH4 and Mg2FeH6 in the reaction. Due to the optimal composition ratio, the composite material exhibited enhanced rehydrogenation and reversibility properties: the temperature and pressure of 673 K and 20 MPa of H2, respectively, for the full rehydrogenation of x = 0.5 composite, were much lower than those required for the partial rehydrogenation of LiBH4. Moreover, the x = 0.5 composite could be reversibly hydrogenated for more than four cycles without degradation of its H2 capacity.
منابع مشابه
The improved Hydrogen Storage Performances of the Multi-Component Composite: 2Mg(NH2)2–3LiH–LiBH4
2Mg(NH2)2–3LiH–LiBH4 composite exhibits an improved kinetic and thermodynamic properties in hydrogen storage in comparison with 2Mg(NH2)2–3LiH. The peak temperature of hydrogen desorption drops about 10 K and the peak width shrinks about 50 K compared with the neat 2Mg(NH2)2–3LiH. Its isothermal dehydrogenation and re-hydrogenation rates are respectively 2 times and 18 times as fast as those of...
متن کاملMetal hydride-based materials towards high performance negative electrodes for all-solid-state lithium-ion batteries.
Electrode performances of MgH2-LiBH4 composite materials for lithium-ion batteries have been studied using LiBH4 as the solid-state electrolyte, which shows a high reversible capacity of 1650 mA h g(-1) with an extremely low polarization of 0.05 V, durable cyclability and robust rate capability.
متن کاملThe role of Ni in increasing the reversibility of the hydrogen release from nanoconfined LiBH4.
Nanoconfinement and the use of catalysts are promising strategies to enhance the reversibility of hydrogen storage in light metal hydrides. We combined nanoconfinement of LiBH4 in nanoporous carbon with the addition of Ni. Samples were prepared by deposition of 5-6 nm Ni nanoparticles inside the porous carbon, followed by melt infiltration with LiBH4. The Ni addition has only a slight influence...
متن کاملDestabilized LiBH4/MgH2 for reversible hydrogen storage
DOE and FreedomCAR technical targets of 6.0 and 9.0 wt.% are set forth capacities to realize a “holy grail” for hydrogen storage systems for 2010 and 2015 respectively. Alkali metal complex hydrides with high theoretical hydrogen capacity, for example: LiBH4 (18 wt.%), are being investigated for their properties to store large quantities of hydrogen. The catalytic doping of SiO2, seems to enhan...
متن کاملNickel Hydrogenation Composite Catalysts Modified by Zirconium in Competitive Benzene Hydrogenation: Effect of Modifiers
A co-impregnation method was applied to the Ni/Zr-HMS/HZSM-5 catalyst (with various amounts of zirconium) during the hydrogenation of benzene. The physicochemical properties of the prepared nickel catalyst were characterized using X - ray diffraction, X - ray fluorescence, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, temperature-programmed desor...
متن کامل