Abstract

Rising global warming concern demands the need for a rapid transition to renewable energy sources. The intermittent nature of these sources emphasizes the requirement of developing highly efficient electrochemical energy storage devices like supercapacitors and batteries. Supercapacitors are at the forefront of powering various devices spanning from electric cars to aircraft. Here, we have engineered the electrode material properties for developing supercapacitors with high capacitance, energy density and cycle life. Among the electrode materials, we have focused on improving the energy storage performance of 2D materials like graphene oxide (GO) and tungsten disulfide (WS2), in addition to metal oxides such as manganese oxide and molybdenum oxide. A simple electrophoretic deposition technique is developed to vertically attach and align 2D materials like GO sheets on the carbon fibers to achieve unprecedented 100,000 charge-discharge cycles. The flexible nature displayed by the manufactured device demonstrated its application for powering next-generation wearable electronics. An all 2D asymmetric supercapacitor developed by combining GO and WS2 electrodes delivered an output voltage beyond the thermodynamic breakdown potential of the aqueous electrolyte. Investigating the structural evolution of these 2D materials using tools such as kelvin probe force microscope (KPFM) and Raman spectroscopy provided an understanding of the surface level chemical and structural changes undergone by the electrodes during cycling. The KPFM is also utilized to successfully engineer the electrode work function to enhance the voltage and energy density in a supercapacitor. This work opened up a new route to obtaining high energy density from supercapacitors which are already exhibiting high power density and cycle life.

Notes

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Graduation Date

2022

Semester

Summer

Advisor

Thomas, Jayan

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Materials Science and Engineering

Degree Program

Materials Science & Engineering

Identifier

CFE0009252; DP0026856

URL

https://purls.library.ucf.edu/go/DP0026856

Language

English

Release Date

August 2022

Length of Campus-only Access

None

Access Status

Doctoral Dissertation (Open Access)

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