Insight into enhanced dehydrogenation of LiBH4 modified by Ti and O from first-principles calculations

•Ti + O co-doped LiBH4 are introduced by Ti substitution for Li and O for B/H.•Modification of Ti + O on enhanced dehydrogenation of LiBH4 depends on occupation sites.•Decrease of Li − B/H and B − H interactions leads to destabilized LiBH4 for favorable H-desorption.•Formation of Ti − H and O − H bo...

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Veröffentlicht in:Computational and theoretical chemistry 2024-08, Vol.1238, p.114718, Article 114718
Hauptverfasser: Hu, Chunyan, Mo, Xiaohua, Zhou, Haojie, Li, Xiulan, Zuo, Xiaoli, Ma, Yu, Jiang, Weiqing
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Sprache:eng
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Zusammenfassung:•Ti + O co-doped LiBH4 are introduced by Ti substitution for Li and O for B/H.•Modification of Ti + O on enhanced dehydrogenation of LiBH4 depends on occupation sites.•Decrease of Li − B/H and B − H interactions leads to destabilized LiBH4 for favorable H-desorption.•Formation of Ti − H and O − H bonds acts as thermodynamic force for LiBH4 destabilization. The present work gives the occupation energies, hydrogen dissociation energies and electronic structures of pure (Li8B8H32/Li16B16H64), Ti-doped (Li7TiB8H32/Li15TiB16H64) and Ti + O co-doped LiBH4 (Li7TiB7OH32/Li15TiB15OH64 and Li7TiB8OH31/Li15TiB16OH63) using first-principles calculations, with the aim of providing new insights into the enhanced dehydrogenation of LiBH4 modified by Ti and O. The results show that Ti + O incorporation in LiBH4 lattice is energetically favorable in terms of occupation energy, relative to Ti adding. Ti and Ti + O modification not only suppresses B2H6 formation upon H-desorption, but also destabilizes LiBH4 for favorable H-desorption. The decreased B − H and Li − B/H interactions contributes to LiBH4 destabilization, and the formed Ti − H and O  H bonds acts as thermodynamic driving force for this destabilization. In our studies, Ti + O enable hydrogen dissociation energy to reach the minimum at Li7TiB7OH32/Li15TiB15OH64 not at Li7TiB8OH31/Li15TiB16OH63. Thus, suitable Ti + O co-substitution is needed to achieve significant enhancement in LiBH4 dehydrogenation.
ISSN:2210-271X
DOI:10.1016/j.comptc.2024.114718