Nanostructured electrode materials for high performance lithium rechargeable batteries

Abstract

Li rechargeable battery is the most promising energy storage device due to its high energy density. Current Li rechargeable battery technology is sufficiently suitable for the application of energy storage device of portable electric devices, however, further investigation is essential for the higher power and energy density applications such as electric vehicles, power tools, and large scale energy storage system. Recently, investigation of nanostructured electrode materials gets much interest due to its nanoscale dimension often offers superior battery performance such as high specific capacity, rate capability, and cyclability originated from improved electrochemical activity, enlarged interface contact area, facile Li ion and electron conduction, and better stress accommodation. In this thesis, fabrication and electrochemical characterization of nanostructured electrode materials is investigated for both anodes ($TiO_2$, $ZnMn_2O_4$) and cathodes (amorphous $FePO_4$, $FeF_3$). Novel fabrication strategies for the nanostructured electrode materials are developed by using, modifying, or combining nanofabrication techniques such as self-assembled peptide templating, atomic layer deposition, hydrothermal synthesis, and mineralization. The fabricated nanostructured electrode materials exhibit excellent battery performance, which means that the fabrication strategies are beneficial for investigating electrode materials for the next-generation Li rechargeable batteries. Nanostructured anatase $TiO_2$ is fabricated by atomic layer deposition of $TiO_2$ onto self-assembled peptide template. The fabricated nanostructured $TiO_2$ has unique morphology composed of three-dimensional network of individual hollow nanoribbons. It shows excellent high rate performance compared to spherical $TiO_2$ nanopowder indicating that controlling the morphology as well as nanoscale dimension is important on battery performance. $ZnMn_2O_4$ nanorod is fabricated from isostructur...