In Situ Synthesis of 3D Flower‐Like Nanocrystalline Ni/C and its Effect on Hydrogen Storage Properties of LiAlH4.

Abstract: Lithium alanate (LiAlH4) is of particular interest as one of the most promising candidates for solid‐state hydrogen storage. Unfortunately, high dehydrogenation temperatures and relatively slow kinetics limit its practical applications. Herein, 3D flower‐like nanocrystalline Ni/C, composed of highly dispersed Ni nanoparticles and interlaced carbon flakes, was synthesized in situ. The as‐synthesized nanocrystalline Ni/C significantly decreased the dehydrogenation temperature and dramatically improved the dehydrogenation kinetics of LiAlH4. It was found that the LiAlH4 sample with 10 wt % Ni/C (LiAlH4‐10 wt %Ni/C) began hydrogen desorption at approximately 48 °C, which is very close to ambient temperature. Approximately 6.3 wt % H2 was released from LiAlH4‐10 wt %Ni/C within 60 min at 140 °C, whereas pristine LiAlH4 only released 0.52 wt % H2 under identical conditions. More importantly, the dehydrogenated products can partially rehydrogenate at 300 °C under 4 MPa H2. The synergetic effect of the flower‐like carbon substrate and Ni active species contributes to the significantly reduced dehydrogenation temperatures and improved kinetics. [ABSTRACT FROM AUTHOR]