Abstract
The fast ionic, high temperature (HT) phase of LiBH4 can be stabilised by Br¯ substitution. Lithium borohydride bromide compounds, Li(BH4)1-xBrx have been synthesized mechanochemically, with and without thermal treatment and the resulting phase behaviour determined as a function of composition. Single phase materials exist for 0.29 ≤ x ≤ 0.50 with conductivity two orders of magnitude higher than LiBH4 at 313 K. Powder neutron diffraction has been used to resolve the details of the crystal structure of one such compound. These demonstrate that 7Li(11BD4)2/3Br1/3 retains the HT structure (hexagonal space group P63mc, a ≈ 4.2 Å, c ≈ 6.7 Å) from 293-573 K. The borohydride bromide exhibits considerable static and dynamic disorder, the latter invoking complex rotational motion of the (BH4)¯ anions.
Original language | English |
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Pages (from-to) | 7780-7787 |
Number of pages | 8 |
Journal | Chemistry of Materials |
Volume | 27 |
Issue number | 22 |
Early online date | 26 Oct 2015 |
DOIs | |
Publication status | E-pub ahead of print - 26 Oct 2015 |
Keywords
- phase behavior
- composition
- crystal structure