CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Hydrogen Storage Capacity Study of a Li+Graphene Composite System with Different Charge States |
SUI Peng-Fei, ZHAO Yin-Chang, DAI Zhen-Hong**, WANG Wei-Tian |
Computational Physics Laboratory, Institute of Opto-electronic Information Technology, Yantai University, Yantai 264005
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Cite this article: |
SUI Peng-Fei, ZHAO Yin-Chang, DAI Zhen-Hong et al 2013 Chin. Phys. Lett. 30 107306 |
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Abstract Based on first-principles plane-wave calculations, we firstly reconfirm that the Li+graphene complex can be taken as a hydrogen storage medium with capacity of 12.8wt%. Then metal adsorption properties of this Li+graphene system with different charge states are investigated. Finally, the hydrogen storage ability of the charging system is calculated. Our calculations show that adding positive charge on a Li+graphene composite results in a conspicuous reduction of Li 2s and Li 2p orbital occupation with respect to the C 2p state. As a result, a stronger bonding between Li and graphene is formed, and a special double-layer hydrogen adsorption structure has been found. Compared to the neutral system, utilizing the positive charged Li+graphene to store hydrogen molecules can solve the issue of clustering of metal atoms after releasing hydrogen, and can improve hydrogen storage capacity up to a gravimetric density of 20.4wt%, correspondingly one adsorbed Li atom can effectively absorb up to seven H2 molecules.
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Received: 10 May 2013
Published: 21 November 2013
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PACS: |
73.22.Pr
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(Electronic structure of graphene)
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81.05.ue
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(Graphene)
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61.48.Gh
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(Structure of graphene)
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71.15.Mb
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(Density functional theory, local density approximation, gradient and other corrections)
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Abstract
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