Abstract

Access to clean, and sustainable energy is one of the biggest challenges of our generation. With the rapid growth of renewable energy harvesters, developing electrochemical energy storage devices (EEDs) that respond well to them is of significant interest. Supercapacitors are a class of EEDs with exceptional power densities and ultra-long cycle life. These properties make them an attractive candidate as a replacement, or to be used in combination with batteries and other EEDs. In this dissertation, nano cerium oxide (nano CeO2) based materials are examined as an active material for supercapacitor applications. The first part of this work details how the morphology and selective crystal planes can lead to significantly improved charge storage; and how a combination of high surface area and exposure of high energy crystal planes ({110}, {100}) can lead up to 1.5 times higher charge storage capacity. The remainder of the thesis examines how nano CeO2 can effectively be used as an additive to improve the electrochemical properties of other supercapacitor materials. The second part describes a method to drastically improve the poor cycle life of conductive polymer-based materials by the addition of nano CeO2 and graphene through scalable spraydrying process. The ternary composite exhibits a high energy density (46.3 Wh Kg-1) and stable cycle life (92% capacitance retention after 6000 cycles). The third part details how nano CeO2 can be used as an active mechanical spacer for graphene aerogel based material. Here, nano CeO2 not only contributes towards charge storage but also prevents the restacking of graphene layers. The hybrid aerogels exhibit a high specific capacitance of 503 F g-1 and minimal capacitance fade after 10,000 cycles. This work highlights how engineering nanostructures beyond simple size reduction can lead to superior electrochemical properties and ultimately EEDs with improved safety, high power, and energy density.

Notes

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Graduation Date

2020

Semester

Spring

Advisor

Seal, Sudipta

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Materials Science and Engineering

Degree Program

Materials Science and Engineering

Format

application/pdf

Identifier

CFE0008415; DP0023851

URL

https://purls.library.ucf.edu/go/DP0023851

Language

English

Release Date

November 2020

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Open Access)

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