Engineering Nanostructured Electrode Composites as High Performance Anode Materials - for Lithium Ion Batteries

This thesis reports on the development and evaluation of the performance of a nanostructured electrode anode for rechargeable lithium ion batteries. The aim is to develop a new material for energy storage with high energy and power densities for wide application in portable electronic devices. The thesis begins by reviewing two approaches to the synthesis and characterization of nanostructured iron oxide based anode for the lithium ion battery. The first approach is the fabrication of various morphologies of iron oxide, and the second involves the addition of various conductive agents, such as graphene, carbon, carbon nanotubes, and others, in order to improve the electrochemical performance of iron oxide anode for next generation energy storage in lithium ion batteries. This thesis uses the second approach to design a three-dimensional material that includes graphene nanosheets (GNS), porous graphitic carbon (PGC), and iron oxide nanoparticles that are synthesized via an in-situ technique. It is found that such nanocomposites of Fe3O4/C/PGC/GNS nanosheets with three-dimensional structure, which are synthesized with different ratios of GNS 10 wt% and 20 wt%, exhibits excellent electrochemical performance when applied as anode in the lithium ion battery over 70 cycles. The reversible capacity of this nanocomposite with 10wt% GNS after 30 cycles at 500 mA/g is 470 and 480 mAh/g for charge-discharge, while for the nanocomposite with 20 wt% GNS, it is 420 and 430 mAh/g for chargedischarge, respectively. The reversible capacity is 97 and 99 mAh/g during chargedischarge at 5000 mA/g current density, respectively, for the 10 wt% GNS sample, while the reversible capacity for the nanocomposite with 20 wt% GNS is 89 and 100 mAh/g during charge-discharge.