Papers by Keyword: Energy Barrier

Abstract: By adopting the first-principles calculation based on density functional theory (DFT), the diffuse pattern and the energy landscape for Li transfer in the LiFePO4 are investigated for the three different directions. The results of relaxed structure are compared with those of the non-relaxed structure and the energy barriers are significantly reduced and the effect of structure relaxation is most obvious for Li displacement along [100] direction. Energy barrier for the Li diffusion along [010] direction is lower than the other two direction in both calculation which indicates that the Li diffusion in LiFePO4 is one dimensional.

Abstract: In this paper presents the study of the process of interaction between helium (He) and methane (СH₄) molecules and the energy barrier created by a single-layer carbon nanotube. The interaction potential fields for the case of a tube as a nano-scale object interacting with single molecules or atoms were determined. Calculations show the dependence of molecular velocity within the symmetry axis of a single-layer carbon nanotube on the axial coordinate. The influence of the tube radius on the character of molecular passage through the open tube is considered.

Abstract: The strain effect on the properties of Li₂MnO₃ cathode material is investigated by means of first principles method. The intercalation potential decreases with the strains at the extent of about 0.1V. The strain effect on the intercalation potential is anisotropic with the strain perpendicular to the host layer brings the largest decrease to the potential. Additionally, the tensile paralleling to the host layer can also open up the migrating pathway of lithium in the transition metal layer. The strain effect on the anomalously large charging capacity of Li₂MnO₃ stabilized LiMO₂ (M = Mn, Ni, Co, etc.) solid solution system is also evaluated from the two factors.

Abstract: Nanofibers are very promising new type of material with a broad range of possible applications. The new NANOSPIDER technology opens a possibility to produce nanofabrics in an amount large enough for them to start being interesting as a construction material. There are many so-called passive applications of nanotextiles (including different types of filters and protective layers), and active applications, when the active chemical agent is incorporated in their structure. In the present paper, however, the new possible application of nanofabrics is proposed: as a base material on which technically interesting nanoclusters are heterogeneously nucleated. The basic thermodynamics of heterogeneous nucleation on nanofibers is considered. The extreme curvature of nanofibers manifests itself in an energetic barrier of nucleation, which is quite different from a case of nucleation on a flat surface. The expression for Gibbs energy of cluster formation is derived, taking into account the elastic strain resulting from a volume (or shape) changes during nucleation.