C N x nanotubes with pyridinelike structures: p-type semiconductors and Li storage materials

Using density functional theory (DFT) computations, we investigated pyridinelike structures in a series of single-walled CN(x) nanotubes and found that tube chirality and diameter play important roles in the formation of pyridinelike structures. Not pyridinelike structures but more N(C) defects (N atoms substituting for C atoms) should be responsible for the experimentally observed donor states of CN(x) nanotubes. The adsorption energies of Li at the pyridinelike defect are so large and the energy barrier for lithium penetrating the defect is so low that CN(x) nanotubes with pyridinelike structures have enhanced capability for lithium storage.