First-principles study of decomposition mechanisms of Mg(BH 4 ) 2 ·2NH 3 and LiMg(BH 4 ) 3 ·2NH 3
- Citation data:
RSC Advances, ISSN: 2046-2069, Vol: 7, Issue: 49, Page: 31027-31032
- Publication Year:
- Chemistry; Chemical Engineering; mg(bh4)2$2nh3; limg(bh4)3$2nh3; first-principles; study; decomposition; mechanisms; Engineering; Physical Sciences and Mathematics
The decomposition mechanisms of Mg(BH)·2NHand LiMg(BH)·2NHwere studied by using density functional theory calculations. Compared to that of Mg(BH)·2NH, the incorporation of LiBHwith the formation of LiMg(BH)·2NHslightly increased Bader charges of B atoms, meanwhile it decreased Bader charges of N atoms. Mg(BH)·2NHshows a low ammonia vacancy diffusion barrier, but relatively high ammonia vacancy formation energy, which lead to a low concentration of NHvacancies and limit NHtransportation. In contrast to that of Mg(BH)·2NH, LiMg(BH)·2NHhas a relatively high ammonia vacancy formation energy and diffusion barrier, which suppresses ammonia release. The incorporation of LiBHand Mg(BH)·2NHdoes not decrease but increases the hydrogen formation barrier of LiMg(BH)·2NH, resulting in a slight increase in the dehydrogenation peak temperature, consistent with experimental results.