Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application

In this study, electrochemical materials, namely MnO2, reduced graphene oxide (rGO), porous carbon nanoparticles (PCNs), and rGO/MnO2 nanocomposite, were prepared in diverse morphologies such as nanoflowers (MnO2), nanosheets (rGO), and nanoparticles (carbon). Different physical and chemical charac...

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Main Author:	Gomaa Abdelgawad, Mohammed Ali
Format:	Thesis
Language:	English
Published:	2015
Subjects:	Q Science (General) QD Chemistry
Online Access:	http://umpir.ump.edu.my/id/eprint/12962/19/Preparation%20and%20characterization%20of%20manganese-based%20and%20carbon-based%20nanomaterials%20for%20supercapasitors%20application.pdf
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spelling	my-ump-ir.129622021-11-02T07:51:06Z Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application 2015-07 Gomaa Abdelgawad, Mohammed Ali Q Science (General) QD Chemistry In this study, electrochemical materials, namely MnO2, reduced graphene oxide (rGO), porous carbon nanoparticles (PCNs), and rGO/MnO2 nanocomposite, were prepared in diverse morphologies such as nanoflowers (MnO2), nanosheets (rGO), and nanoparticles (carbon). Different physical and chemical characterizations have been conducted to study the structural and morphological properties of the materials under study. Electrochemical properties of the above materials have been studied comprehensively using cyclic voltammetry (CV), galvanostatic charge–discharge (CDC) and electrochemical impedance spectroscopy (EIS) in order to evaluate their suitability as an electrode for supercapacitive energy storage. MnO2 nanoflowers was recovered from spent batteries by a combining leaching and electrowinning techniques. The recovered MnO2 nanoflowers exhibited high specific capacitance (Cs) (303 F g-1 at 5 mV s-1). Furthermore, MnO2 was electrodeposited by potentiostatic and galvanostatic conditions. Under similar electrodeposition conditions, MnO2 deposited by galvanostatic condition showed smaller particle size, less compact layered structure and wider band gap compared to potentiostatic deposition. The galvanostatic MnO2 rendered facile ions diffusion, low resistances and showed superior capacitive behavior. The rGO nanosheets were prepared by hydrazine reduction of graphene oxide and their electrochemical properties were studied. The rGO showed high Cs of 191 and 168 F g-1 at 5 mV s-1, in 5 M KOH and 1 M Na2SO4, respectively and high cycling stability > 96 % over 1000 cycles. In addition, PCNs with fine particles size of 35 nm were prepared from oil palm leaves using a catalyst free process. The Cs of PCNs is 245 and 213 F g-1 at 5 mV s-1 in 5 M KOH and 1 M Na2SO4, respectively. The PCNs showed high cycling stability of 95 %. Practical supercapacitors were developed using rGO and PCNs; the devices delivered energy densities ~18 and ~25 W h kg-1 at power densities 340 and 360 W kg-1, respectively, under wider operating voltage window of 2 V in neutral electrolyte. rGO/MnO2 nanocomposite has been prepared by simultaneous electrochemical conversion of GO and Mn3O4. The Cs of rGO/MnO2 is 457 F g-1 at 5 mV s-1, which are several folds higher compared to those for pure rGO and MnO2. Furthermore, rGO/MnO2 showed high stability of 95 % over 2000 CDC cycles. Therefore, the present study identifies electrochemical materials with improved energy storage capabilities. 2015-07 Thesis http://umpir.ump.edu.my/id/eprint/12962/ http://umpir.ump.edu.my/id/eprint/12962/19/Preparation%20and%20characterization%20of%20manganese-based%20and%20carbon-based%20nanomaterials%20for%20supercapasitors%20application.pdf pdf en public phd doctoral Universiti Malaysia Pahang Faculty of Industrial Sciences & Technology
institution	Universiti Malaysia Pahang Al-Sultan Abdullah
collection	UMPSA Institutional Repository
language	English
topic	Q Science (General) QD Chemistry
spellingShingle	Q Science (General) QD Chemistry Gomaa Abdelgawad, Mohammed Ali Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
description	In this study, electrochemical materials, namely MnO2, reduced graphene oxide (rGO), porous carbon nanoparticles (PCNs), and rGO/MnO2 nanocomposite, were prepared in diverse morphologies such as nanoflowers (MnO2), nanosheets (rGO), and nanoparticles (carbon). Different physical and chemical characterizations have been conducted to study the structural and morphological properties of the materials under study. Electrochemical properties of the above materials have been studied comprehensively using cyclic voltammetry (CV), galvanostatic charge–discharge (CDC) and electrochemical impedance spectroscopy (EIS) in order to evaluate their suitability as an electrode for supercapacitive energy storage. MnO2 nanoflowers was recovered from spent batteries by a combining leaching and electrowinning techniques. The recovered MnO2 nanoflowers exhibited high specific capacitance (Cs) (303 F g-1 at 5 mV s-1). Furthermore, MnO2 was electrodeposited by potentiostatic and galvanostatic conditions. Under similar electrodeposition conditions, MnO2 deposited by galvanostatic condition showed smaller particle size, less compact layered structure and wider band gap compared to potentiostatic deposition. The galvanostatic MnO2 rendered facile ions diffusion, low resistances and showed superior capacitive behavior. The rGO nanosheets were prepared by hydrazine reduction of graphene oxide and their electrochemical properties were studied. The rGO showed high Cs of 191 and 168 F g-1 at 5 mV s-1, in 5 M KOH and 1 M Na2SO4, respectively and high cycling stability > 96 % over 1000 cycles. In addition, PCNs with fine particles size of 35 nm were prepared from oil palm leaves using a catalyst free process. The Cs of PCNs is 245 and 213 F g-1 at 5 mV s-1 in 5 M KOH and 1 M Na2SO4, respectively. The PCNs showed high cycling stability of 95 %. Practical supercapacitors were developed using rGO and PCNs; the devices delivered energy densities ~18 and ~25 W h kg-1 at power densities 340 and 360 W kg-1, respectively, under wider operating voltage window of 2 V in neutral electrolyte. rGO/MnO2 nanocomposite has been prepared by simultaneous electrochemical conversion of GO and Mn3O4. The Cs of rGO/MnO2 is 457 F g-1 at 5 mV s-1, which are several folds higher compared to those for pure rGO and MnO2. Furthermore, rGO/MnO2 showed high stability of 95 % over 2000 CDC cycles. Therefore, the present study identifies electrochemical materials with improved energy storage capabilities.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Gomaa Abdelgawad, Mohammed Ali
author_facet	Gomaa Abdelgawad, Mohammed Ali
author_sort	Gomaa Abdelgawad, Mohammed Ali
title	Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
title_short	Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
title_full	Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
title_fullStr	Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
title_full_unstemmed	Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
title_sort	preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application
granting_institution	Universiti Malaysia Pahang
granting_department	Faculty of Industrial Sciences & Technology
publishDate	2015
url	http://umpir.ump.edu.my/id/eprint/12962/19/Preparation%20and%20characterization%20of%20manganese-based%20and%20carbon-based%20nanomaterials%20for%20supercapasitors%20application.pdf
_version_	1783731972240048128

Preparation and characterization of manganese-based and carbon-based nanomaterials for supercapasitors application

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