- You are here:
Dissertation Defense – Yohan "Johnny" Park
MSE Grad Presentation
Monday, October 22, 2018 - 10:00am
Committee Members: Prof. Joseph W. Perry, Advisor, CHEM Prof. Zhiqun Lin, Co-Advisor, MSE Prof. Bernard Kippelen, ECE Prof. Mark Losego, MSE Prof. Seung Woo Lee, ME
“Modification of a Hybrid Sol-Gel Dielectric and BaTiO3 for Capacitors with Ultrahigh Energy Density”
Demand for energy storage systems that are more efficient and capable of storing greater amounts of energy is increasing in parallel with the growing global need to both save energy and improve energy conversion. Batteries, capacitors and fuel cells have been essential to this effort to develop advanced energy storage devices. Traditionally, owing to their high power density, capacitors have been widely used for decades in various areas such as electronics, defense and medical fields. Capacitors have additional advantages including fast charging and discharging and long cycle life. Despite these clear strengths, the low energy density of capacitors has limited their more widespread use.
In this work, three approaches have been studied in an effort to improve the electrical properties of capacitors including energy density and breakdown strength. First, organic charge blocking layers such as poly(p-phenylene oxide) (PPO) and octadecylphosphonic acid (ODPA) were introduced on 2-cyanoethyltrimethoxysilane (CNETMS) sol-gel films to reduce leakage current and improve energy density. Second, atomic layer deposition (ALD) was used to fabricate thin metal oxide films as a charge blocking layer in capacitors with CNETMS. Lastly, barium titanate (BT) nanoparticles were coated with zirconia (ZrO2) shells in order to mitigate the large gap in permittivity between BT nanoparticles and polymeric hosts.