THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

GEORGIA INSTITUTE OF TECHNOLOGY

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, December 20, 2016

11:00 AM
in MRDC 4211

will be held the

DISSERTATION PROPOSAL DEFENSE

for

Dong-Chan Lee

“Iron Anode for Nickel-Iron Batteries”

Committee Members:

Prof. Gleb Yushin, Advisor, MSE
Prof. Faisal Alamgir, Co-advisor, MSE
Prof. Meilin Liu, MSE
Prof. Thomas F. Fuller, ChBE
Prof. Seung Woo Lee, ME

Abstract:

The field of energy generation has grown by developing the systems to harvest energy from renewable sources such as solar and wind. While their improvement was sought, a demand for large-scale energy storage systems has continuously arisen to store the excess energy during the electricity producing periods and release it during the electricity demanding periods. Although lithium-ion batteries are widely used due to their high energy density and efficiency, the simultaneous demand on cost, safety and durability for the gird-scale applications presents a tremendous challenge to the deployment of such commercially available systems. Indeed, exploring aqueous battery systems is expected to bring the benefit of low-cost materials and non-flammable electrolytes.

Since Ni-Fe batteries were invented and commercialized by Waldemar Jungner and Thomas Edison in 1897 – 1902, respectively, they have been used in various stationary and mobile applications for over 70 years in USA and Europe until the 1980s when the iron-based batteries were largely supplanted by sealed lead-acid batteries. Though they were in hibernation for a few decades, a renewed interest on them awakes due to their environmental friendliness, low cost, long life and robustness against harsh conditions as well as the compatibility with intermittent power sources such as wind power and photovoltaics (PV).

The challenge for improved Ni-Fe batteries, however, remains limiting their utilization for large-scale electricity grid: electrolyte decomposition, high self-discharge, poor cell efficiency, and low energy & power densities. Such drawbacks are mainly originated from the hydrogen evolution reaction (HER) on the surface of iron anode. As a parasitic reaction competing with charging reaction for anode, HER causes low round-trip performance of cells as well as undesired electrolyte consumption. Furthermore, the passivation of iron contributes to low capacity utilization which ceases at around 1/3 of theoretical capacity of main reaction. Since the passivation belongs to an oxidation process of iron which is the discharge reaction for anode, it is crucial to investigate the reactions that iron undergoes during the charge/discharge in alkaline media in terms of both physical and chemical change in iron anode.

Overall, the development of novel method to reduce HER accompanied with sound understanding on cell reactions will bring the performance enhancement for Ni-Fe batteries. Here, I propose the research on i) the microstructure (physical) and phase (chemical) change of iron particles during charge/discharge in alkaline cells, and ii) the adjustment on cell/operation conditions to find the room for reducing HER and improving the electrochemical performance of iron anode.