Date of Award

1-1-2018

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

College/School/Department

Department of Nanoscale Science and Engineering

Program

Nanoscale Sciences

Content Description

1 online resource (ii, x, 130 pages) : illustrations (some color)

Dissertation/Thesis Chair

Harry Efstathiadis

Committee Members

Laura Schultz, Manisha V Rane-Fondacaro, Hassaram Bakhru, Carl Ventrice

Keywords

Ammonium, EDLC, Electrolyte, Supercapacitor, Ultracapacitor, Electric double layer, Supercapacitors, Electrochromic devices, Nanostructured materials

Subject Categories

Nanoscience and Nanotechnology

Abstract

Electric Double Layer Capacitors (EDLC) are high power (103 W kg-1), durable (>500,000 cycles) energy storage devices that are promising candidates for Hybrid Energy Storage Systems (HESS) , automotive and smart grid applications. EDLCs when coupled with lithium ion batteries in HESS configurations for hybrid vehicles have been shown to reduce capacity related degradation by a factor of 2 and impedance related degradation by 5.9. Despite these promising advantages, the adoption of EDLCs has been hampered due to concerns regarding the low volumetric and gravimetric energy density of these devices. Researchers have attempted to address these concerns through the development of high surface area nanomaterials for electrodes and high stability ionic liquids. These approaches, although technically successful, have failed to displace the incumbent materials, activated carbon and tetraethyl ammonium tetrafluoroborate in acetonitrile, due to the high cost of these designer materials. This research aims to increase the energy density of EDLCs through the use of modified cations that are compatible with current commercial devices and investigate the impact of the cation structure on electrochemical characteristics of the system.

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