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    Fabrication and Investigation of Co3O4 Sponged Shape Nanostructured Supercapacitor Layer Electrodes Modified by Graphene

    , Ph.D. Dissertation Sharif University of Technology Qorbani, Mohammad (Author) ; Moshegh, Alireza (Supervisor) ; Naseri, Naima (Supervisor)
    Abstract
    Recently, Supercapacitors, as one of the most important energy storage devices, have attracted attensions by the scientists. Supercapcitor devices with appoporate design can store energy by two different mechanisms: i) physical (like conventional capacitors, i.e. by using polarization of the electrolyte, and ii) formation of electric double layer) and chemical mechanisms (like batteries, with reversible faradic reactions). These energy storage mechanisms allow these devices not only store high energy density but also they can provide high power density. In this project, two Co3O4/Co(OH)2 and Co3O4@Sponge-like rGO electrodes are made with chemical and electrochemical methods. To characterize... 

    Synthesis and Characterization of 3D Reduced Graphene Oxide with Phosphorus and Nitrogen Dopants as an Efficient Supercapacitor Electrode Material

    , M.Sc. Thesis Sharif University of Technology Nazari, Neda (Author) ; Malek Khachatourian, Adrineh (Supervisor)
    Abstract
    Supercapacitors are safe and environmentally friendly energy storage devices that have been considered for their diverse applications. One of the most important factors that control supercapacitors' capacity is the electrode material's structure and properties. Adding heteroatoms or composite materials synthesis is one way to improve electrode performance. In this study, a facile, fast, and economical hydrothermal method was used to synthesize N doped, P doped or N/P co-doped 3D reduced graphene oxide (rGO) for high-performance supercapacitor application. Nitrogen and phosphorus elements were replaced by carbon atoms simultaneously during the graphene oxide hydrothermal reduction procedure.... 

    Synthesis of MXene/Polyaniline Composite as an Electrode Material for Supercapacitors

    , M.Sc. Thesis Sharif University of Technology Borzou, Mohadeseh (Author) ; Khachatourian, Adrineh Malek (Supervisor) ; Bagheri, Reza (Supervisor) ; Esfandiar, Ali (Co-Supervisor)
    Abstract
    Titanium carbide MXene (Ti_3 C_2 T_x) has attracted significant research interest because of its extraordinary advantages as advanced electrode material for energy storage. In this study, 4-aminodiphenylamine functionalized Ti_3 C_2 T_x/polyaniline composite synthesized by in situ growth of PANI on 4-aminodiphenylamine functionalized Ti_3 C_2 T_x nanosheets. First, Ti_3 C_2 T_x MXene nanosheets was prepared according to the minimally intensive layer delamination (MILD) method followed by sonication. Ti_3 C_2 T_x nanosheets were modified with 4-aminodiphenylamine diazonium salt. The FTIR، FE-SEM and EDS analysis were used to characterize modified Ti_3 C_2 T_x. Finally, the Ti_3 C_2 T_x... 

    Comparison of the Performance of Nanostructured Metal Oxides and Metal Sulfides as Electrode Active Materials in the Construction of Supercapacitors

    , M.Sc. Thesis Sharif University of Technology Molaei Zarandi, Zeynab (Author) ; Ghotbi, Cyrus (Supervisor) ; Khorasheh, Farhad (Supervisor) ; Asgharinezhad, Ali Akbar (Supervisor) ; larimi, Afsaneh Sadat (Supervisor)
    Abstract
    High-capacity electrode materials are crucial for enhancing the performance of supercapacitors. Transition metal sulfides are considered promising materials for supercapacitor applications due to their high theoretical capacity and good electrical conductivity. Additionally, cerium oxide improves the performance of supercapacitors due to stable reversible oxidation states and greatly supported the faradaic redox reaction. In this study, ceria nanosheets incorporated with MCoS (M=Mn, Zn, Cu) were synthesized successfully through a facile hydrothermal method by sulfidation of MCo LDH/CeO2. The structural and morphological characteristics were analyzed using X-ray diffraction, scanning electron... 

    Facile synthesis of nanoporous CuS nanospheres for high-performance supercapacitor electrodes

    , Article Journal of Energy Chemistry ; Volume 26, Issue 4 , 2017 , Pages 762-767 ; 20954956 (ISSN) Heydari, H ; Moosavifard, S. E ; Shahraki, M ; Elyasi, S ; Sharif University of Technology
    Abstract
    In recent years, development of high-performance supercapacitor electrode materials has stimulated a great deal of scientific research. The electrochemical performance of a supercapacitor strongly depends on its material structures. Herein, we report a simple strategy for high-performance supercapacitors by building pseudocapacitive CuS nanospheres with nanoporous structures, nanosized walls (<10 nm) and relatively large specific surface area of 65 m2/g. This electrode demonstrates excellent electrochemical performance including a maximum specific capacitance of 814 F/g at 1 A/g, significant rate capability of 42% capacitance retention at an ultrafast rate of 50 A/g, and outstanding... 

    Hierarchical Co3O4/Co(OH)2 nanoflakes as a supercapacitor electrode: experimental and semi-empirical model

    , Article ACS Applied Materials and Interfaces ; Volume 7, Issue 21 , 2015 , Pages 11172-11179 ; 19448244 (ISSN) Qorbani, M ; Naseri, N ; Moshfegh, A. Z ; Sharif University of Technology
    American Chemical Society  2015
    Abstract
    In this research, facile and low cost synthesis methods, electrodeposition at constant current density and anodization at various applied voltages, were used to produce hierarchical cobalt oxide/hydroxide nanoflakes on top of porous anodized cobalt layer. The maximum electrochemical capacitance of 601 mF cm-2 at scan rate of 2 mV s-1 was achieved for 30 V optimized anodization applied voltage with high stability. Morphology and surface chemical composition were determined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analysis. The size, thickness, and density of nanoflakes, as well as length of the porous anodized Co layer were measured about 460 ± 45 nm,... 

    Preparation of Conductive and Semi-Conductive Nanocomposites based on Biocompatible Polymers and Investigation of their Conductive, Mechanical and Electrochemical Properties

    , Ph.D. Dissertation Sharif University of Technology Doroudian, Mohadeseh (Author) ; Pourjavadi, Ali (Supervisor)
    Abstract
    In this study, conductive and semi-conductive nanocomposites based on biocompatible and biodegradable polymers were prepared and their applications in different areas were studied. Considering huge environmental contaminants derived from various industries, biodegradable polymers (synthetic or natural) have attracted more attention in industrial and biological applications. Aside from their eco-friendly properties, there are other advantages such as availability, different chemical structures, uniqe physical properties and capability to improve their characteristics.One way to improve the properties of the biocompatible polymers is fabrication of their composites with different materials to... 

    Synthesis and characterization of NiCo2O4 nanorods for preparation of supercapacitor electrodes

    , Article Journal of Solid State Electrochemistry ; Vol. 19, Issue. 1 , 2014 , pp. 269-274 ; ISSN: 1432-8488 Jokar, E ; Zad, A. I ; Shahrokhian, S ; Sharif University of Technology
    Abstract
    Here, a solvothermal method for synthesis of porous Ni–Co binary oxide (NiCo2O4) nanorods followed by thermal decomposition is described. The prepared nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer Emmett Teller (BET) methods. These porous NiCo2O4 nanostructures were promising candidates in the development of high capacity supercapacitors and having excellent cycling performance due to high specific surface area. In addition, the influence of annealing rate on the structure and electrochemical behavior of the synthesized nanorods was investigated. The results showed that the annealing rate had a direct effect on the crystalline... 

    Nanoporous CuS nano-hollow spheres as advanced material for high-performance supercapacitors

    , Article Applied Surface Science ; Volume 394 , 2017 , Pages 425-430 ; 01694332 (ISSN) Heydari, H ; Moosavifard, S. E ; Elyasi, S ; Shahraki, M ; Sharif University of Technology
    Elsevier B.V  2017
    Abstract
    Due to unique advantages, the development of high-performance supercapacitors has stimulated a great deal of scientific research over the past decade. The electrochemical performance of a supercapacitor is strongly affected by the surface and structural properties of its electrode materials. Herein, we report a facile synthesis of high-performance supercapacitor electrode material based on CuS nano-hollow spheres with nanoporous structures, large specific surface area (97 m2 g−1) and nanoscale shell thickness (<20 nm). This interesting electrode structure plays a key role in providing more active sites for electrochemical reactions, short ion and electron diffusion pathways and facilitated... 

    Fabrication and the electrochemical activation of network-like MnO2 nanoflakes as a flexible and large-area supercapacitor electrode

    , Article Journal of Solid State Electrochemistry ; Volume 22, Issue 11 , 2018 , Pages 3507-3514 ; 14328488 (ISSN) Mardi, S ; Moradlou, O ; Moshfegh, A. Z ; Sharif University of Technology
    Abstract
    Porous network-like MnO2 thick films are successfully synthesized on a flexible stainless steel (SS) mesh using a simple and low-cost electrodeposition method followed by an electrochemical activation process. Morphology, chemical composition, and crystal structure of the prepared electrodes before and after the activation process are determined and compared by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analyses. The results show that the implementation of the electrochemical activation process does not change the chemical composition and crystal structure of the films, but it influences the surface morphology of the MnO2... 

    Silver fiber fabric as the current collector for preparation of graphene- based supercapacitors

    , Article Electrochimica Acta ; Volume 227 , 2017 , Pages 246-254 ; 00134686 (ISSN) Mehrabi Matin, B ; Shahrokhian, S ; Iraji zad, A ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    During the past few years, a considerable attention has been devoted to the development of textile- based energy storage devices and wearable electronics applications. In this paper, for the first time, we report a flexible high performance graphene-based supercapacitor using silver fiber fabric as the current collector. The silver fiber fabric offers remarkable advantages such as light weight, mechanical flexibility and ease of integration with electronic textiles, which well-suited for wearable energy storage devices. A new hybrid material of graphene-silver fiber fabric (rGO/SFF) was prepared through a facile electrophoretic deposition of graphene and being used as a binder-free flexible... 

    An efficient two-step approach for improvement of graphene aerogel characteristics in preparation of supercapacitor electrodes

    , Article Journal of Energy Storage ; Volume 17 , 2018 , Pages 465-473 ; 2352152X (ISSN) Jokar, E ; Shahrokhian, S ; zad, A. I ; Asadian, E ; Hosseini, H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    We fabricated a high rate capability supercapacitor based on fluorine-doped graphene-carbon nanotubes aerogel network (G-CNT-F). Based on the electrochemical impedance spectroscopy data, the fluorination decreases the charge transfer resistance of graphene sheets, while CNTs act as spacer in the 3D structure. Therefore, both treatments improved the electrochemical properties of the resulted aerogel. Based on the Fourier transform infrared spectroscopy and XPS results, these excellent performances are attributed to semi-ionic bonds between fluorine and carbon. The specific capacitance of the graphene aerogel showed 78% decrease, when discharge current increases from 2 to 40 mA, while the... 

    Synthesis and characterization of rGO/Fe2O3 nanocomposite as an efficient supercapacitor electrode material

    , Article Journal of Materials Science: Materials in Electronics ; Volume 31, Issue 17 , 2020 , Pages 14998-15005 Abasali karaj abad, Z ; Nemati, A ; Malek Khachatourian, A ; Golmohammad, M ; Sharif University of Technology
    Springer  2020
    Abstract
    The reduced graphene oxide-Fe2O3 (rGO-Fe2O3) nanocomposites were synthesized by a facile and low-cost hydrothermal method employing rGO and Iron (III) nitrate precursors. The synthesis parameters including the reduction time and presence of reduction aid are studied. The structural and morphological studies of the nanocomposites were investigated by using Raman spectra, Fourier transform infrared spectroscopy, X-ray diffraction, and field emission scanning electron microscopy. The results indicate that Fe2O3 nanoparticles with average particle size of 25 nm are well anchored on graphene sheets and the weight percent of the nanoparticles in the nanocomposites was influenced by the reduction... 

    Cobalt based Metal Organic Framework/Graphene nanocomposite as high performance battery-type electrode materials for asymmetric Supercapacitors

    , Article Journal of Energy Storage ; 2020 Azadfalah, M ; Sedghi, A ; Hosseini, H ; Kashani, H ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    Recently, development of advanced materials of metal-organic frameworks (MOFs) has attracted attention for the fabrication of supercapacitors (SCs) because of their high surface area and high level of porosity. However, poor electrical conductivity and weak mechanical properties of the MOFs have restricted their applications in the field. In this study, a one-step, in-situ synthesis of Cobalt-based MOF with graphene (CoMG nanocomposite) was employed to overcome the poor properties of MOFs. Accordingly, when the nanocomposite (CoMG5) was use as a supercapacitor electrode material, a specific capacitance (CS) of 549.96 F g−1 was observed in a three-electrode system with 6 M KOH electrolyte... 

    Hybrid energy storage device from binder-free zinc-cobalt sulfide decorated biomass-derived carbon microspheres and pyrolyzed polyaniline nanotube-iron oxide

    , Article Energy Storage Materials ; Volume 25 , March , 2020 , Pages 621-635 Hekmat, F ; Hosseini, H ; Shahrokhian, S ; Unalan, H. E ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    High-performance supercapacitors that merit superior power and energy densities, as well as long-term cycle durability are always of great significance as a building block of energy storage devices. Herein, an innovative strategy is developed to design hierarchical and unique porous structures of ternary metal sulfide nano-flake decorated porous hydrothermal carbon microspheres. Hierarchical microspheres of ternary zinc-cobalt sulfide nanosheet (NS) decorated biomass derived hydrothermal carbon spheres (HTCSs) are directly employed as the positive supercapacitor electrodes. In addition, composites of pyrolyzed polyaniline nanotubes (PPNTs) and iron oxide, receiving advantages from highly... 

    Cobalt based metal organic framework/graphene nanocomposite as high performance battery-type electrode materials for asymmetric supercapacitors

    , Article Journal of Energy Storage ; Volume 33 , 2021 ; 2352152X (ISSN) Azadfalah, M ; Sedghi, A ; Hosseini, H ; Kashani, H ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    Recently, development of advanced materials of metal-organic frameworks (MOFs) has attracted attention for the fabrication of supercapacitors (SCs) because of their high surface area and high level of porosity. However, poor electrical conductivity and weak mechanical properties of the MOFs have restricted their applications in the field. In this study, a one-step, in-situ synthesis of Cobalt-based MOF with graphene (CoMG nanocomposite) was employed to overcome the poor properties of MOFs. Accordingly, when the nanocomposite (CoMG5) was use as a supercapacitor electrode material, a specific capacitance (CS) of 549.96 F g−1 was observed in a three-electrode system with 6 M KOH electrolyte...