Reactive hydride composites are good candidates for solid hydrogen storage due to their high gravimetric capacity, cyclability, and suitable thermodynamic properties. The LiNH2-MgH2 system is promising as changes in stoichiometry and milling conditions may result in tailoring of these properties. In this work, LiNH2-MgH2 with different ratios (Li2:Mg, Li:Mg) and ball milling conditions (100, 600 rpm) were investigated. Thermal desorption profiles shows hydrogen release starting at 125 degrees C for Li2:Mg 600 sample and at 225 degrees C for Li:Mg 600 sample, while for Li:Mg 100 sample simultaneous hydrogen and ammonia release at 175 degrees C is observed. In-situ synchrotron X-ray diffraction shows the related structural transformations, such as formation of Mg(NH2)(2) and allotropic transformation of alpha into beta-Li2Mg(NH)(2) for Li2:Mg 600 sample at 350 degrees C or direct formation of beta-Li2Mg(NH)(2) for Li:Mg 100 sample at 370 degrees C. Different polymorphs of the LiMgN phase were also observed during cooling for these two samples. For the Li:Mg 600 sample, transformation occurs in a unique reaction from an unknown phase into beta-Li2Mg(NH)(2) at 290 degrees C.

Hydrogen release and structural transformations in LiNH2-MgH2 systems

BARICCO, Marcello
2011-01-01

Abstract

Reactive hydride composites are good candidates for solid hydrogen storage due to their high gravimetric capacity, cyclability, and suitable thermodynamic properties. The LiNH2-MgH2 system is promising as changes in stoichiometry and milling conditions may result in tailoring of these properties. In this work, LiNH2-MgH2 with different ratios (Li2:Mg, Li:Mg) and ball milling conditions (100, 600 rpm) were investigated. Thermal desorption profiles shows hydrogen release starting at 125 degrees C for Li2:Mg 600 sample and at 225 degrees C for Li:Mg 600 sample, while for Li:Mg 100 sample simultaneous hydrogen and ammonia release at 175 degrees C is observed. In-situ synchrotron X-ray diffraction shows the related structural transformations, such as formation of Mg(NH2)(2) and allotropic transformation of alpha into beta-Li2Mg(NH)(2) for Li2:Mg 600 sample at 350 degrees C or direct formation of beta-Li2Mg(NH)(2) for Li:Mg 100 sample at 370 degrees C. Different polymorphs of the LiMgN phase were also observed during cooling for these two samples. For the Li:Mg 600 sample, transformation occurs in a unique reaction from an unknown phase into beta-Li2Mg(NH)(2) at 290 degrees C.
2011
Inglese
Esperti anonimi
509S
S719
S723
4
FRANCIA
GERMANIA
PAESI BASSI
262
7
Pottmaier D.; Dolci F.; Orlova M.; Vaughan G.; Fichtner M.; Lohstroh W.; Baricco M.
info:eu-repo/semantics/article
none
03-CONTRIBUTO IN RIVISTA::03A-Articolo su Rivista
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/87843
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 15
  • ???jsp.display-item.citation.isi??? 16
social impact