Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors
Thesis (PhD)--University of Pretoria, 2016.
Saved in:
| Other Authors: | |
|---|---|
| Format: | Thesis |
| Language: | English |
| Published: |
University of Pretoria
2016
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613500902211584 |
|---|---|
| access_status_str | Open Access |
| author2 | Ozoemena, Kenneth I. |
| author_browse | Ozoemena, Kenneth I. |
| author_facet | Ozoemena, Kenneth I. |
| collection | Thesis |
| dc_rights_str_mv | © 2016 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Thesis (PhD)--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/57254 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:08.629Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/57254 Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors Ozoemena, Kenneth I. u04361822@tuks.co.za Makgopa, Katlego UCTD Thesis (PhD)--University of Pretoria, 2016. This thesis reports on the study of carbon nanomaterials integrated with nanostructured birnessite-type MnO2 and tetragonal hausmannite-type Mn3O4 as electrode materials for enhanced performance in symmetric pseudocapacitors. This work further explores the synergistic effect of graphene oxide decorated with particles of nickel (II) tetraaminophthalocyanine as electrode materials for improved performance (power and energy densities) in symmetrical pseudocapacitor device. Physical properties of the synthesised electrode materials were investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), gas adsorption technique (BET), infra-red spectroscopy, Raman spectroscopy and thermogravimetric analysis (TGA) techniques. Electrochemical properties of synthesised electrode materials were investigated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). From the study of carbon nanomaterials integrated with nanostructured birnessite-type MnO2, it has been discovered that OLC/MnO2 nanohybrid exhibited better performance (regarding specific capacitance, rate capability, and energy density) compared to other nanohybrids such as CNT/MnO2, GO/MnO2, and AC/MnO2. This device gave maximum specific capacitance of 255 F g-1, the specific energy density of 5.6 Wh kg-1 and excellent power density of 74.8 kW kg-1. The CNT/MnO2, exhibited a maximum specific capacitance, energy and power density of 174 F g-1, 4.9 Wh kg-1, and 55.1 kW kg-1, respectively, while, the GO/MnO2 displayed 135 F g-1, 3.9 Wh kg-1, and 35.8 kW kg-1, and AC/MnO2 was 110 F g-1, 3.3 Wh kg-1, and 30.0 kW kg-1, respectively. From the study of carbon nanomaterials integrated with nanostructured tetragonal hausmannite-type Mn3O4, OLC/Mn3O4 nanohybrid exhibited better performance (regarding specific capacitance, rate capability, and energy density) compared to other nanohybrid electrode materials (i.e., CNT/Mn3O4 GO/Mn3O4, and AC/Mn3O4). This device exhibited a maximum specific capacitance of 195 F g-1, the specific energy density of 4.3 Wh kg-1 and power density of 52 kW kg-1. The CNT/Mn3O4 exhibited a maximum specific capacitance, energy and power density of was 180 F g-1, 3.9 Wh kg-1, and 33 kW kg-1, respectively. While the GO/Mn3O4 displayed values of 160 F g-1, 3.6 Wh kg-1, 24 kW kg-1 and AC/Mn3O4 was 124 F g-1, 2.8 Wh kg-1, 18 kW kg-1, respectively. The study on the synergistic effect of graphene oxide (GO) decorated with particles of nickel (II) tetraaminophthalocyanine (NiTAPc) resulted in GO/NiTAPc nanohybrid displaying better pseudocapacitive performance relative to its precursor (i.e., GO and NiTAPc). This pseudocapacitor device exhibited a maximum specific capacitance of 163 F g-1, the specific energy density of 3.6 Wh kg-1 and high-power density of 140 kW kg-1. These values are much higher than those of its individual precursors NiTAPc (60 F g-1 and 1.3 Wh kg-1) and GO (15 F g-1 and 0.3 Wh kg-1). This excellent capacitive performance shows promising opportunities for the development of aqueous-based pseudocapacitors made of carbon nanomaterials with transitional metal oxides and metallophthalocyanine (MPc) complexes (N4-macrocyclic metal compounds). Interestingly, this study also shows the significance of the use of novel carbon nanomaterials apart from the well-studied activated carbon for the development of high-power electrochemical capacitors. tm2016 Chemistry PhD Unrestricted 2016-10-14T07:32:54Z 2016-10-14T07:32:54Z 2016-09-01 2016 Thesis Makgopa, K 2016, Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors, PhD Thesis, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/57254> S2016 http://hdl.handle.net/2263/57254 en © 2016 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| title | Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| title_full | Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| title_fullStr | Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| title_full_unstemmed | Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| title_short | Effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| title_sort | effects of carbon nanomaterials on the performance of symmetric pseudocapacitors |
| topic | UCTD |
| url | http://hdl.handle.net/2263/57254 |