Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications

Development of pseudocapacitors, in which electrical charge is stored through a redox reaction when it is brought in contact with an electrolyte, is an active area of research to achieve high energy density (ES) and power density (PS) in supercapacitors. Many promising materials such as RuO2, -MnO2...

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Main Author:	Radhiyah, Abd Aziz
Format:	Thesis
Language:	English
Published:	2016
Subjects:	HD Industries Land use Labor Q Science (General)
Online Access:	http://umpir.ump.edu.my/id/eprint/15846/13/Synthesis%20and%20characterization%20of%20layered%20alkaline%20manganates%2C%20titanates%2C%20and%20molybdates%20for%20supercapacitor%20applications.pdf
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spelling	my-ump-ir.158462021-11-25T00:45:01Z Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications 2016-08 Radhiyah, Abd Aziz HD Industries. Land use. Labor Q Science (General) Development of pseudocapacitors, in which electrical charge is stored through a redox reaction when it is brought in contact with an electrolyte, is an active area of research to achieve high energy density (ES) and power density (PS) in supercapacitors. Many promising materials such as RuO2, -MnO2, Co3O4 are proposed as desirable pseudocapacitor electrodes; however, they are either poorly abundant and toxic or resistive and difficult to be synthesized. On the other hand, there are several highly abundant transition metal oxides exhibiting poor and/or non-capacitive behavior such as titanium dioxide (TiO2) and some polymorphs of manganese oxide (-MnO2). It is hypothesized that making a layered structure of the above metal oxides could enhance their electrochemical performance because the lamellar space between the layers could easily intercalate/de-intercalate of ions. Consequently, this thesis aims to synthesize layered analogues of TiO2, -MnO2 by incorporating hydrated alkaline ions and study their electrochemical properties. Effect of incorporating hydrated alkaline ions in an intrinsically layered material, i.e., Mo9Se11, on its electrochemical properties has also been undertaken to make a contrast. The physicochemical characterization was analyzed using X-ray diffraction (XRD), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM), transmission electron microscope (HRTEM) and Brunauer-Emmett-Teller (BET) surface analyzer. The electrochemical properties of the samples were studied by cyclic voltammetry (CV), galvanostatic charge-discharge cycling (GCD) and electrochemical impedance spectroscopy (EIS) in a three-electrode system configuration. A comprehensive investigation on the structure and properties of the materials before and after incorporation has been undertaken and the results are discussed deeply. It showed that alkaline layered structure of manganate and titanate material exhibits ~2.5 and ~16 times higher specific capacitance (CS) than that of the non-layered ones in optimized electrolytes. However, alkaline layered molybdate material shows 6 times lower CS value than non-alkaline layered structure. The capacitive performance was correlated with the characteristic resistance and time of the electrodes employing EIS. The energy storage capability of the layered structure materials is evaluated by assembling asymmetric supercapacitors (ASC) using the layered materials as anode and commercial activated carbon as cathode. The electrochemical performance of ASCs were compared with the symmetric device fabricated using the commercial activated carbon (AC). The best performing ASCs delivered ES of ~63, ~17, and ~42 Wh/kg at PS of ~962, ~600, and ~960 W/kg for Na-MnO2//AC, Na2Ti2O4(OH)2//AC, and Mo9Se11//AC cells in the optimized electrolytes of 1M LiOH, 1M KOH and 3M LiOH, respectively, which are an order of magnitude higher than that achieved by the AC//AC device. Among them, Na-MnO2//AC showed ~98% retention of charge storage, which is much superior to the other devices; therefore, this device is promising to further develop for commercial applications. 2016-08 Thesis http://umpir.ump.edu.my/id/eprint/15846/ http://umpir.ump.edu.my/id/eprint/15846/13/Synthesis%20and%20characterization%20of%20layered%20alkaline%20manganates%2C%20titanates%2C%20and%20molybdates%20for%20supercapacitor%20applications.pdf pdf en public phd doctoral Universiti Malaysia Pahang Faculty of Industrial Sciences and Technology
institution	Universiti Malaysia Pahang Al-Sultan Abdullah
collection	UMPSA Institutional Repository
language	English
topic	HD Industries Land use Labor Q Science (General)
spellingShingle	HD Industries Land use Labor Q Science (General) Radhiyah, Abd Aziz Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
description	Development of pseudocapacitors, in which electrical charge is stored through a redox reaction when it is brought in contact with an electrolyte, is an active area of research to achieve high energy density (ES) and power density (PS) in supercapacitors. Many promising materials such as RuO2, -MnO2, Co3O4 are proposed as desirable pseudocapacitor electrodes; however, they are either poorly abundant and toxic or resistive and difficult to be synthesized. On the other hand, there are several highly abundant transition metal oxides exhibiting poor and/or non-capacitive behavior such as titanium dioxide (TiO2) and some polymorphs of manganese oxide (-MnO2). It is hypothesized that making a layered structure of the above metal oxides could enhance their electrochemical performance because the lamellar space between the layers could easily intercalate/de-intercalate of ions. Consequently, this thesis aims to synthesize layered analogues of TiO2, -MnO2 by incorporating hydrated alkaline ions and study their electrochemical properties. Effect of incorporating hydrated alkaline ions in an intrinsically layered material, i.e., Mo9Se11, on its electrochemical properties has also been undertaken to make a contrast. The physicochemical characterization was analyzed using X-ray diffraction (XRD), selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscope (FESEM), transmission electron microscope (HRTEM) and Brunauer-Emmett-Teller (BET) surface analyzer. The electrochemical properties of the samples were studied by cyclic voltammetry (CV), galvanostatic charge-discharge cycling (GCD) and electrochemical impedance spectroscopy (EIS) in a three-electrode system configuration. A comprehensive investigation on the structure and properties of the materials before and after incorporation has been undertaken and the results are discussed deeply. It showed that alkaline layered structure of manganate and titanate material exhibits ~2.5 and ~16 times higher specific capacitance (CS) than that of the non-layered ones in optimized electrolytes. However, alkaline layered molybdate material shows 6 times lower CS value than non-alkaline layered structure. The capacitive performance was correlated with the characteristic resistance and time of the electrodes employing EIS. The energy storage capability of the layered structure materials is evaluated by assembling asymmetric supercapacitors (ASC) using the layered materials as anode and commercial activated carbon as cathode. The electrochemical performance of ASCs were compared with the symmetric device fabricated using the commercial activated carbon (AC). The best performing ASCs delivered ES of ~63, ~17, and ~42 Wh/kg at PS of ~962, ~600, and ~960 W/kg for Na-MnO2//AC, Na2Ti2O4(OH)2//AC, and Mo9Se11//AC cells in the optimized electrolytes of 1M LiOH, 1M KOH and 3M LiOH, respectively, which are an order of magnitude higher than that achieved by the AC//AC device. Among them, Na-MnO2//AC showed ~98% retention of charge storage, which is much superior to the other devices; therefore, this device is promising to further develop for commercial applications.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Radhiyah, Abd Aziz
author_facet	Radhiyah, Abd Aziz
author_sort	Radhiyah, Abd Aziz
title	Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
title_short	Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
title_full	Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
title_fullStr	Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
title_full_unstemmed	Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
title_sort	synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications
granting_institution	Universiti Malaysia Pahang
granting_department	Faculty of Industrial Sciences and Technology
publishDate	2016
url	http://umpir.ump.edu.my/id/eprint/15846/13/Synthesis%20and%20characterization%20of%20layered%20alkaline%20manganates%2C%20titanates%2C%20and%20molybdates%20for%20supercapacitor%20applications.pdf
_version_	1783732004385193984

Synthesis and characterization of layered alkaline manganates, titanates, and molybdates for supercapacitor applications

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