Effects of Li doping on H-diffusion in MgH2: A first-principles study

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Publication Type pre-print
School or College College of Engineering
Department Materials Science & Engineering
Creator Liu, Feng
Other Author Ming, Wenmei; Fang, Zhigang Zak
Title Effects of Li doping on H-diffusion in MgH2: A first-principles study
Date 2013-01-01
Description The effects of Li doping in MgH2 on H-diffusion process are investigated, using first-principles calculations. We have identified two key effects: (1) The concentration of H vacancy in the þ1 charge state ðVþ1 H Þ can increase by several orders of magnitude upon Li doping, which significantly increases the vacancy mediated H diffusion rate. It is caused by the preferred charge states of substitutional Li in the 1 state ðLi1 MgÞ and of interstitial Li in the þ1 state ðLiþ1 i Þ, which indirectly reduce the formation energy of Vþ1 H by up to 0.39eV depending on the position of Fermi energy. (2) The interaction between Vþ1 H and Li1 Mg is found to be attractive with a binding energy of 0.55 eV, which immobilizes the Vþ1 H next to Li1 Mg at high Li doping concentration. As a result, the competition between these two effects leads to large enhancement of H diffusion at low Li doping concentration due to the increased H-vacancy concentration, but only limited enhancement at high Li concentration due to the immobilization of H vacancies by too many Li.
Type Text
Publisher American Institute of Physics (AIP)
Volume 114
Issue 24
Language eng
Bibliographic Citation Ming, W., Fang, Z. Z., & Liu, F. (2013). Effects of Li doping on H-diffusion in MgH2: A first-principles study. Journal of Applied Physics, 114(24), no.243502.
Rights Management (c)American Institute of Physics. The following article appeared in Ming, W., Fang, Z. Z., & Liu, F. Journal of Applied Physics, 114(24) 2013. and may be found at http://dx.doi.org/10.1063/1.4853055.
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Identifier uspace,18338
ARK ark:/87278/s6r530qm
Setname ir_uspace
Date Created 2014-02-20
Date Modified 2014-02-20
ID 711318
Reference URL https://collections.lib.utah.edu/ark:/87278/s6r530qm
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