MnO2 continues to gain traction in the research and development of advanced
supercapacitor materials due to its arsenal of advantages, such as high capacitance, low cost,
natural abundance, and environmental benignity. However, its low conductivity has hindered its
adoption into real-life applications. Compositing MnO2 with conductive additives has proved to
be a promising route for the improvement of its power-energy characteristics. Four novel
colloidal techniques were developed for the synthesis of MnO2-CNT composites with enhanced
performance at high active mass loading. One strategy utilized a Schiff-based linkage of
dispersants such as 3,4-Dihydroxybenzaldehyde (DHB) and Toluidine Blue O (TDB) to
effectively mix and disperse MnO2 and CNT. Secondly, a co-dispersion technique was also
investigated using Gallocyanine to improve dispersion and mixing of MnO2 and MWCNT.
Third, a novel liquid-liquid extraction technique opened new avenues in agglomerate-free
processing of individual components, which allowed enhanced electrode performance. Lastly, a
morphology-modification strategy was also undertaken by synthesizing MnO2 nanorods with the
use of advanced organic dispersants to control the aspect ratio and composite nanorods with
MWCNT.
The second major material investigated was polypyrrole (PPy), a polymer material with
high conductivity, ease of synthesis, low-cost, and non-toxicity. However, its low cyclic stability
was prevented it from being applied for real-world applications. Certain anionic and aromatic
dopants have shown to improve the conductivity and cyclic stability. Therefore, one of the
investigations in this work attempted to improve the performance of PPy-CNT composites by
use of a novel anionic dopant, Sunset Yellow (SY). For all investigations electrodes with high mass loadings were produced to achieve high areal capacitance, thus ensuring the practicality of the
techniques / Thesis / Master of Applied Science (MASc) / Supercapacitors (SCs) and batteries are both electrochemical energy storage devices.
While batteries excel at storing energy in high volumes, supercapacitors excel in charging (and
discharging) at extremely high rates. It is desirable to obtain the best of both worlds in a single
device; high energy volume and fast charging speeds. Although such a feat is not out of the
realm of theoretical possibility, current projections forecast supercapacitors to compliment
battery technologies instead of replacing them. Nonetheless, constant progression in the field of
SCs is needed to sustain and proliferate their adoption into emerging markets. Therefore, the aim
of this research was to assist in the endeavours to improve current SC technologies from a
materials science standpoint.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/24659 |
| Date | January 2019 |
| Creators | Syed, Aseeb |
| Contributors | Zhitomirsky, Igor, Materials Science and Engineering |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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