No abstract

Electrode material characteristics need to be improved urgently to fulfill the requirements for high performance lithium ion batteries. Herein, we report the use of the two-phase alloy Ti 80 Co 20 for the growth of Ti-Co-O nanotubes (NT) employing an anodic oxidation process in a formamide-based electrolyte containing NH 4 F. The surface morphology and the current density for the initial nanotube formation are found to be dependent on the crystal structure of the alloy phases. XPS analyses of the grown nanotube arrays along with the oxidation state of the involved elements confirmed the formation of TiO 2 /CoO nanotubes under the selected process conditions.The electrochemical performance of the grown nanotubes was evaluated against a Li/Li + electrode at different current densities of 10 -400 µA cm -2 . The results revealed that TiO 2 /CoO nanotubes prepared at 60 V exhibited the highest areal capacity of ~ 600 µAh cm -2 (i.e. 315 mAh g -1 ) at a current density of 10 µA cm -2 . At higher current densities TiO 2 /CoO nanotubes showed nearly doubled lithium ion intercalation and a coulombic efficiency of 96 % after 100 cycles compared to lower effective TiO 2 nanotubes prepared under identical conditions. The observed enhancement in the electrochemical performances could be attributed to increasing Li ion diffusion resulting from the presence of CoO nanotubes and the high surface area of the grown oxide tubes. The TiO 2 /CoO electrodes preserved their tubular structure after electrochemical cycling with only little changes in morphology.

A new fundamental mechanism for reliable engineering of zinc oxide (ZnO) nanorods to nanoplatelets grafted Mo8O23-MoO2 mixed oxide with controlled morphology, composition and precise understanding of the nanoscale reaction mechanism was developed. These hybrid nanomaterials are gaining interest due to their potential use for energy, catalysis, biomedical and other applications. As an introductory section, we demonstrate a new expansion for the concept ‘materials engineering’ by discussing the fabrication of metal oxides nanostructures by bottom-up approach and carbon nanoparticles by top-down approach. Moreover, we propose a detailed mechanism for the novel phenomenon that was experienced by ZnO nanorods when treated with phosphomolybdic acid (PMA) under ultra-sonication stimulus. This approach is expected to be the basis of a competitive fabrication approach to 2D hybrid nanostructures. We will also discuss a proposed mechanism for the catalytic deposition of Mo8O23-MoO2 mixed oxide over ZnO nanoplatelets. A series of selection rules (SRs) which applied to ZnO to experience morphology transition and constitute Abdelmohsen theory for morphology transition engineering (ATMTE) will be demonstrated through the article, besides a brief discussion about possibility of other oxides to obey this theory.

No abstract

No abstract