THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Monday, December 19, 2016

3:00 PM
in MRDC 3515

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Anirudh Ramanujapuram

"Degradation mechanisms of electrodes in high voltage aqueous lithium-ion batteries"

Committee Members:

Prof. Gleb Yushin, Advisor, MSE

Prof. Faisal Alamgir, MSE

Prof. Preet Singh, MSE
Prof. Matthew McDowell, ME
Prof. Marta Hatzell, ME

Abstract:

Lithium-ion batteries are the most popular energy devices for almost all equipment today. From cell-phones and laptops, to advanced uses in automotive and aircraft applications, lithium-ion batteries have slowly taken over the market. Unfortunately, today’s lithium-ion batteries are also highly unsafe. They rely heavily on organic solvents for electrolytes in the battery. These organic solvents are inherently flammable in nature and have caused several fires reported in batteries over the past few years. 

In this research, we aim to replace this flammable liquid with a safer alternative such as water. Water-based batteries offer greatly improved safety and much lower cost (from lower raw material cost to open air manufacturing). In addition, water based electrolytes have faster ionic mobility for lithium ions and thus can be potentially used for much faster charging batteries or batteries with thicker electrodes.

We will discuss the electrochemical performance characteristics and stability of LCO in as a cathode in aqueous electrolytes. While LCO has been demonstrated to cycle for 20-100 cycles in aqueous environments the causes of its degradation have not been investigated in detail. Our studies demonstrated that LCO cathodes with remarkably stable performance showing only 13 % fading after over 1500 cycles. Post mortem analysis of the electrodes was conducted to understand the effect of cycling and the causes of degradation. Electrolyte composition was found to have a dramatic impact on the electrochemical performance and stability of LCO in aqueous environments. 

Current work focuses on understanding the performance and degradation mechanism of titanium dioxide (TiO2 – anatase) in high concentration aqueous electrolytes. Literature has shown that TiO2 can be cycled in TiO2 at high rates, but the fundamental understanding of why TiO2 degrades in aqueous electrolytes is still unknown.