Data di Pubblicazione:
2011
Abstract:
The new concept, anion substitution, is explored for possible improvement of hydrogen storage properties
in the system LiBH4–LiI. The structural chemistry and the substitution mechanism are analyzed using
Rietveld refinement of in situ synchrotron radiation powder X-ray diffraction (SR-PXD) data, attenuated
total reflectance infrared spectroscopy (ATR-IR), differential scanning calorimetry (DSC) and Sieverts
measurements. Anion substitution is observed as formation of two solid solutions of Li(BH4)1−xIx, which
merge into one upon heating. The solid solutions have hexagonal structures (space group P63mc) similar
to the structures of h-LiBH4 and -LiI. The solid solutions have iodide contents in the range
∼0–62 mol%
and are stable from below room temperature to the melting point at 330 ◦C. Thus the stability of the
solid solutions is higher as compared to that of the orthorhombic and hexagonal polymorphs of LiBH4
and - and -LiI. Furthermore, the rehydrogenation properties of the iodide substituted solid solution
Li(BH4)1−xIx, measured by the Sieverts method, are improved as compared to those of LiBH4. After four
cycles of hydrogen release and uptake the Li(BH4)1−xIx solid solution maintains 68% of the calculated
hydrogen storage capacity in contrast to LiBH4, which maintains only 25% of the storage capacity after
two cycles under identical conditions.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
hydrogen storage; Lithium borohydride; Anion substitution; In situ powder X-ray diffraction; Sieverts method; Infrared spectroscopy
Elenco autori:
Line H Rude; Elena Groppo; Lene M Arnbjerg; Dorthe B Ravnsbæk; Regitze R
Aagaard; Yaroslav Filinchuk; Marcello Baricco; Flemming Besebacher; Torben R. Jensen
Link alla scheda completa:
Pubblicato in: