In situ synchrotron radiation powder X-ray diffraction study of the 2LiNH sub(2) + LiH + KBH sub(4) system

• Published in: Journal of alloys and compounds Vol. 580; pp. S278 - S281
• Main Authors: Sale, Maddalena, Pistidda, Claudio, Taras, Alessandro, Napolitano, Emilio, Milanese, Chiara, Karimi, Fahim, Dornheim, Martin, Garroni, Sebastiano, Enzo, Stefano, Mulas, Gabriele
• Format: Journal Article
• Language: English
• Published: 15.12.2013
• Subjects: Alloys; Differential scanning calorimetry; Diffraction; Reflection; Strontium; Synchrotron radiation; Transformations; X-rays
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2013.02.175

In the present work we focus on the 2LiNH sub(2) + KBH sub(4) + LiH system: the phase-structural transformations occurring during the desorption process on the powder mixture are described by in situ synchrotron radiation powder X-ray diffraction (SR-PXD), high-pressure differential scanning calorimetry and manometric measurements. It is observed that LiNH sub(2) transforms into Li sub(2)NH during heating, at about 160 [degrees]C, while the reflections related to KBH sub(4) disappeared at 380 [degrees]C. At higher temperature, the formation of Li sub(3)BN sub(2) is detected, together with an evident increase of the background, ascribable to the presence of a further phase in the molten state. Patterns at room temperature, after cooling down the sample, confirm the presence of Li sub(3)BN sub(2) and KH as reported in the theoretical study. For the as prepared mixture it is possible to achieve the theoretical hydrogen gravimetric capacity of 7.4 wt%.