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.
(Density functional theory, local density approximation, gradient and other corrections)
引用本文:
. [J]. 中国物理快报, 2013, 30(10): 107306-107306.
SUI Peng-Fei, ZHAO Yin-Chang, DAI Zhen-Hong, WANG Wei-Tian. Hydrogen Storage Capacity Study of a Li+Graphene Composite System with Different Charge States. Chin. Phys. Lett., 2013, 30(10): 107306-107306.
2013, Vol. 30 
