Mechanism of Li Adsorption on Carbon Nanotube-Fullerene Hybrid System: A First-Principles Study

The lithium (Li) adsorption mechanism on the metallic (5,5) single wall carbon nanotube (SWCNT)-fullerene (C60) hybrid material system is investigated using first-principles method. It is found that the Li adsorption energy (−2.649 eV) on the CNT-C60 hybrid system is lower than that on the peapod system (−1.837 eV) and the bare CNT (−1.720 eV), indicating that the Li adsorption on the CNT-C60 hybrid system is more stable than on the peapod or bare CNT system. This is due to the C60 of high electron affinity and the charge redistribution after mixing CNT with C60. In order to estimate how efficiently Li can utilize the vast surface area of the hybrid system for increasing energy density, the Li adsorption energy is calculated as a function of the adsorption positions around the CNT-C60 hybrid system. It turns out that Li preferably occupies the mid-space between C60 and CNT and then wraps up the C60 side and subsequently the CNT side. It is also found that the electronic properties of the CNT-C60 system, s...