The density functional theory within the Kohn-Sham approach, the pseudopotential method, and sets of plane waves are using to compare the electronic structures of single-wall carbon nanotubes (SWCNT) interacting with Cu and Li atoms. It has been found that neutral Cu+SWCNT and Li +SWCNT systems (armchair or zigzag) possess the metallic electronic states near the Fermi level. The charged (either negative or positive) Cu +SWCNT and Li+SWCNT armchair systems also have the metallic-like electronic structure. However the charged Cu+SWCNT and Li+SWCNT zigzag systems have energy gaps at the Fermi region; and the negative charged systems are more favorable energetically than the positive charged systems. The Cu-zigzag system has the gap of 1.2 eV; and the gap of the Li-zigzag is 1.7 eV. As the energy gap at the level of Fermi prevents leaving of a charge from the charged Cu+SWCNT and Li+SWCNT systems, the systems can work as negative electrodes for the power accumulator. Thus, the electrical charge can be effectively accumulated in these systems. Electrical characteristics of the Cu+SWCNT system are close to those of the Li+SWCNT system, and at the same time the Cu +SWCNT systems are more stable and cheaper than Li+SWCNT ones, thus they are perspective for production of new power sources.
