The Structure of Carbon Nanotube Exohedral Complexes with Lithium in a Wide Range of Concentrations

Abstract

The sorption properties of the outer surface of carbon nanotubes with respect to lithium are studied in connection with the search for new materials for lithium battery electrodes. The regularities of the atom ensemble structure with the increased adsorbate concentration have been investigated using ab initio method of computer modeling. Carbon nanotubes (7.7) fragment containing 112 carbon and up to 50 lithium atoms was studied. It is shown that the process of the sequential filling of the nanotube surface by adsorbate consists of two stages. The first of them (the concentration of Li is less than 8 – 9 at. %): distribution of adsorbate atoms on the surface of the tube is determined by the Coulomb repulsion of lithium ions. Chemical interaction between lithium atoms becomes significant at concentration 9 at. %. It leads to the formation of structures such as trimers and tetramers of lithium.