Access Type

Open Access Dissertation

Date of Award

January 2014

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Chemical Engineering and Materials Science

First Advisor

K. Y. S. Ng

Second Advisor

Steven O. Salley

Abstract

Due to rapid increase in energy demand, modern society necessitates to develop high power, light-weight, and more economical energy storage systems. Rechargeable Li-ion batteries and Li-oxygen batteries have become the most promising energy devices in terms of energy and power densities. Diverse research on these battery components is being carried out by researchers worldwide to improve power density to meet the future requirements. The possible routes to improving power density of Li-ion as well as Li-oxygen batteries is to use nanostructured, hybrid electrode materials since they can significantly enhance kinetics of electrochemical reactions; and ion-conducting, low volatile electrolytes since they can improve ionic diffusion and transport properties.

This dissertation focuses on a systematic approach in developing highly efficient SnO2 and Sn electrodes for rechargeable Li-ion batteries and ionic-liquid electrolytes for rechargeable Li-oxygen batteries. SnO2/graphene nanohybrids and carbon-coated SnO2 as well as Sn nanostructured materials are prepared using new approaches and optimized conditions to achieve high Li-ion battery performances. Systematic structural, morphological, and electrochemical studies are performed to understand the influence of carbon additive/coating as well as particle size/inter-particle spacing on the specific capacity, rate capability, and cycling performance. These studies provide insights into design and development of anode materials for high power Li-ion batteries.

One of the biggest challenges hindering development of rechargeable, non-aqueous Li- O2 battery is the selection of a stable electrolyte in the oxidative environment. In the present study, ternary mixed ionic-liquid electrolytes consisting of pyrrolidinium [N-butyl-N-methylpyrrolidinium+ (PYR14+)] and imidazolium [1-butyl-3-methylimidazolium+ (BMIM+)] based bis(trifluoromethylsulfonyl) imide (TFSI-) with LiTFSI salt is investigated. The influence of ratio between PYR14+ and BMIM+ species as well as total concentration of electrolyte on the Li-O2 battery performance is studied.

Download

Share

COinS