▎ 摘　　要

Hydrogen storage performance of Li decorated graphene oxide ( GO) under an external electric field was investigated with the first-principle method based on the density functional theory ( DFT) calculations. Firstly the stability of Li@ GO structure due to the adsorption of Li atoms at different binding sites on GO structure was investigated. Then a stable Li@ GO structure was obtained and dependences of the structural stability and H-2 adsorption of the Li@ GO structure on the electric field were discussed. The results indicate that both the H-2 adsorption energy, E-ad, and the distance between H-2 and Li atom, d( Li-H-2), decrease with the increasing intensity of the downward electric field. While both Ead and d(Li-H-2) increase with the increasing intensity of the upward electric field. From the partial density of state( PDOS) analysis, the H-2-Li hybridization peaks under a negative electric field shifted to the larger negative energy region compared to those without an electric field, which indicates the H-2-Li @ GO system becomes more stable under the negative electric field. When the positive electric field was added, the H-2-Li hybridization peaks shifted to the smaller negative energy region, which indicates the interaction between H-2 and Li becomes weaker. It is therefore anticipated that the adsorption-desorption processes of H-2 on Li @ GO structure can be easily controlled by adding an electric field with appropriate intensity and direction. Further calculation indicates the Li @ GO structure has a maximum hydrogen storage capability of larger than 3. 1% without the external electric field.