Li adsorption on a Fullerene-Single wall carbon nanotube hybrid system: Density functional theory approach

Abstract

In this study, we investigate Li adsorption mechanisms on the C-60-SWCNT hybrid system using density functional theory. It is found that the Li adsorption energy of the C-60-SWCNT hybrid system is increased in comparison to that of the pure SWCNT. The Li adsorption energy ranges from -1.917 eV to -2.642 eV for the single-Li adsorbed system and from -2.351 eV to -2.636 eV for the double-Li adsorbed system. It is also found that the adsorption energy becomes similar at most positions throughout the structure. In addition, the Li adsorption energy of 31-Li system is calculated to be -1.863 eV, which is significantly lower than the Li-Li binding energy (-1.030 eV). These results infer that Li atoms will be adsorbed on the space 1) between C-60 and C-60; 2) between SWCNT and C-60; 3) the rest of the space (e. g. between SWCNTs), rather than form Li clusters. As more Li atoms are adsorbed onto the C-60-SWCNT hybrid system due to such improved Li adsorption capability, the metallic character of the system is enhanced, which is confirmed via the band structure and electronic density of states. (C) 2014 Elsevier B.V. All rights reserved.