Density functional theory (DFT) study on the effects of Li+ doping on electronic states of graphene

✍ Scribed by Hiroto Tachikawa; Yoshinori Nagoya; Takahiro Fukuzumi

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 953 KB
• Volume: 195
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2010.01.014

✦ Synopsis

The electronic structures of a lithium ion (Li + ) doped-graphene at the ground and low-lying excited states have been investigated by means of density functional theory (DFT) method. A graphene composed of 19 benzene rings was used as a model of graphene, while the edge carbon atom was terminated by hydrogen atom (expressed by C 54 H 18 ). The geometry optimization showed that the Li + ion binds to a hexagonal site where six carbon atoms interact equivalently to the Li + ion. When the Li + ion interacts with the graphene surface, the electronic configuration of the Li + ion is changed from (1s) 2 (2s) 0 to (1s) 2 (2s) 0.01 (2p) 0 (3p) 0.02 , suggesting that the sp-hybridization of lithium ion is important in the adsorption to the graphene surface. The band gap of graphene is slightly red-shifted by the doping of Li + ion due to the interaction with the sp-hybrid orbital. The effects of Li + on both the ground and excited electronic states of graphene were discussed on the basis of theoretical results.