Supercapacitors have emerged as a promising energy storage technology with unique
characteristics that set them apart from conventional batteries and capacitors. Supercapacitors
bridge the gap between these two technologies by combining the high power
density of capacitors with the high energy storage capacity of batteries, offering a compelling
solution for various applications. In the pursuit of enhancing supercapacitor performance,
magnetite (Fe3O4) has been researched as a potential anode material. Fe3O4
offers several desirable properties, including high theoretical capacitance, low cost, and
environmental friendliness. Compositing Fe3O4 with conductive additives has served to
address the issue of limited conductivity in Fe3O4 anodes for practical uses, however, a
focus must be shifted to enhancing the capacitive performance of such anodes to unlock
their full potential. Achieving the full potential of Fe3O4 for supercapacitor applications
requires addressing challenges in the colloidal fabrication of high-active mass electrodes.
This is done by exploring the exceptional adsorption properties of two dispersing and
capping agents: 3,4-dihydroxybenzoic acid and murexide.
Exceptional adsorption properties of catecholate-type 3,4-dihydroxybenzoic acid molecules
were explored for surface modification of Fe3O4 nanoparticles to enhance their colloidal
dispersion as verified by sedimentation test results and Fourier-transform infrared spectroscopy
measurements. Electrodes prepared in the presence of 3,4-dihydroxybenzoic
acid exhibited nearly double the capacitance at slow charging rates as compared to the
control samples without the dispersant or with benzoic acid as a non-catecholate dispersant.
Density functional theory analysis of adsorption behavior of 3,4-dihydroxybenzoic
acid and benzoic acid at the (001) surface of Fe3O4 corroborated these experimental results
by providing an understanding of the basic mechanism of 3,4-dihydroxybenzoic
acid adsorption on the surface of nanoparticles.
Furthermore, murexide for surface modification of Fe3O4 nanoparticles effectively enhanced
the performance of multi-walled carbon nanotube-Fe3O4 supercapacitor anodes.
Our experimental results demonstrate significant improvements in electrode performance
when murexide is used as a capping or dispersing agent compared to the case with no
additives. From impedance measurements, we revealed a substantial decrease in the real
part of impedance for samples prepared with murexide, indicating easier charge transfer
at more negative electrode potentials, and reinforcing the role of murexide as a capping
agent and charge transfer mediator. The theoretical investigation allowed us to identify
the nature of chemical bonds between murexide and the surface, with significant charge
transfer taking place between the Fe3O4 surface and murexide adsorbate. / Thesis / Master of Applied Science (MASc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/29110 |
| Date | 11 1900 |
| Creators | Boucher, Coulton |
| Contributors | Rubel, Oleg, Zhitomirsky, Igor, Materials Science and Engineering |
| Source Sets | McMaster University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
Page generated in 0.0022 seconds