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

• Li adsorption mechanisms on the C60-SWCNT hybrid system.
• C60-SWCNT hybrid system is increased the Li adsorption energy.
• C60-SWCNT hybrid system improved the metallic character.
• Li atoms will be adsorbed on the hybrid system rather than form Li cluster.

In this study, we investigate Li adsorption mechanisms on the C60-SWCNT hybrid system using density functional theory. It is found that the Li adsorption energy of the C60-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 C60 and C60; 2) between SWCNT and C60; 3) the rest of the space (e.g. between SWCNTs), rather than form Li clusters. As more Li atoms are adsorbed onto the C60-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.