The first-principles calculations are performed to investigate the geometric stability and the hydrogen storage capacity of lithium-decorated oxidized porous graphene (PG). Due to strong interaction between Li and O atom, two stable Li decorated structures have relatively high Li binding energies of 3.84 and 3.04 eV, which could eliminate the clustering problem for Li atoms on PG surface. One doped Li atom could hold five H2 molecules and the binding energy of each H2 is above 0.2 eV. The interaction of H2 molecules with Li atom results from charge exchange between H2's σ orbital and Li's 2s orbital. In the final structure with two Li-O groups in one carbon pore, a hydrogen storage capacity of 9.43 wt. % could be achieved. By the combination of the advantage of Li decoration and oxidized porous graphene, Li-OPG possesses remarkable geometric stability and high hydrogen storage capacity.
Received 25 September 2012Accepted 27 November 2012Published online 20 December 2012
This research work was supported by National Natural Science Foundation of China (Grant No. 61172003) and Innovative Foundation of Huazhong University of Science and Technology (Grant No. 2012QN151). Computational resources provided by Center of Computational Material Design and Measurement Simulation, Huazhong University of Science and Technology.
Article outline: I. INTRODUCTION II. COMPUTATIONAL METHODS III. RESULTS AND DISCUSSION A. Li-OPG structure B. Hydrogen binding energy of Li-OPG C. Hydrogen storage capacity of Li-OPG IV. CONCLUSIONS
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