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specific-capacitance
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Adsorption Processes in Capacitive Deionization
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
Today the water crisis affects billions around the world.According to existance of large amount of salty water on the earth, it seems one of the best soloution is desalination of salty water.There are methods for removing ions from water such as thermal methods, membrane methods , chemical methods and capacitive deionization.Capacitive deionization is based on the deviation of ions in the electric field.CDI system contains of two conductive porous electrodes that an elecric field is applied between them.While the brine pass through the space between the elecrodes the ions are absorbed by elecrodes. After a while the electrodes get saturated so a reverse potential is needed to regenerate the...
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 ; 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...
Role of nitrogen doping at the surface of titanium nitride thin films towards capacitive charge storage enhancement
, Article Journal of Power Sources ; Volume 359 , 2017 , Pages 349-354 ; 03787753 (ISSN) ; Chaker, M ; Achour, H ; Arman, A ; Islam, M ; Mardani, M ; Boujtita, M ; Le Brizoual, L ; Djouadi, M. A ; Brousse, T ; Sharif University of Technology
Abstract
We recently reported an impressive cycling stability (over 20,000 cycles) of titanium nitride (TiN) electrodes with high specific capacitance. It is anticipated that nitrogen (β−N) doping in the oxidized surface of TiN film plays a crucial role in charge storage mechanism and stability of this material. In this work, we offer an evidence on the effect of β−N doping on improvement in specific capacitance of vacuum annealed TiN thin films. The annealing of the TiN films leads to the diffusion of the excess β−N from sub-surface to oxidized TiN film surface without further oxidation of the electrode surface. We demonstrate an increase in the TiN areal capacitance upon an increase in the amount...
Synthesis and Characterization of Supercapacitor Electrodes Based on Graphene and MnO2 Nanostructure
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor) ; Moradlou, Omran (Co-Advisor)
Abstract
Supercapacitors represent a new class of energy storage devices that have been attracted many researchers in last few years. Graphene with unique properties such as superior electrical conductivity and large specific surface area is one of the most suitable materials in supercapacitor applications. Besides, metal oxides are being used as active compounds in supercapacitors due to their role in redox reactions. In this research, synthesis and characterization of supercapacitor electrodes based on graphene and MnO2 nanostructured materials was studied under different conditions. For this purpose, Graphene oxide (GO) was synthesized by Hummers’ method and then, it was deposited on a nickel foam...
Electrochemical Preparation and Study of Transitional Metal Mixed Oxides as Supercapacitor Electrodes
, Ph.D. Dissertation Sharif University of Technology ; Gobal, Fereydoon (Supervisor)
Abstract
In this thesis, the improving effects of deposited metal oxides onto or next to each other and the advantages of every metal oxide were considered. In the next step, the substrate improvement was studied and the porous metal oxides with ideal supercapacitive properties with porosity increase of substrate were obtained.CoFeO2 supercapacitor was prepared by chronoamperometric ethod.CoFeO2waselectrodeposited at room temperature and presents wide potential window and good capacitive properties in comparison with other metal oxides.Layers of cobalt and manganese oxides were co-deposited or deposited on top of each other or next to each other by chronometric method onto stainless steel substrate....
Synthesis of carbon-based spinel nico2o4 nanocomposite and its application as an electrochemical capacitor
, Article Journal of Electronic Materials ; Volume 46, Issue 8 , 2017 , Pages 4948-4954 ; 03615235 (ISSN) ; Elyasi, S ; Heydari, H ; Dalir, N ; Sharif University of Technology
Springer New York LLC
2017
Abstract
In this study, a thermal method was used to synthesize spinel NiCo2O4 and carbon nanotubes (CNTs)@NiCo2O4 with an average size 50 nm and 20 nm, respectively. Addition of CNTs into NiCo2O4 noticeably increases the active surface area compared to pure spinel NiCo2O4. SEM analyses showed that the morphologies are spherical in both pure and composite samples. Uniform CNTs@NiCo2O4 nanoparticles exhibit high specific capacitance of 210 F g−1 at 2 A g−1 and a good retention capacity of 92.70% after 2500 cycles, which shows a considerable improvement compared to NiCo2O4. Additionally, an exceptional rate capability of about 73.2% was obtained at 50 A g−1. Such remarkable electrochemical performance...
Electric field enhanced synthesis of copper hydroxide nanostructures for supercapacitor application
, Article Nano ; Volume 12, Issue 1 , 2017 ; 17932920 (ISSN) ; Ghasemi, S ; Sanaee, Z ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2017
Abstract
Electric field enhanced approach has been used to synthesize different copper hydroxide morphologies as high-performance supercapacitors electrode materials. Employing this efficient, simple and low cost method, various shapes such as rod, flower and cube with an average grain size of 30nm to 1μm were obtained on the copper substrate. The results revealed that applied electric field considerably accelerates the formation time of nanostructures from several days to close to 1min, where some of the desired nanostructures were obtained even in 1s. The electrochemical properties of different morphologies were compared using cyclic voltammograms and charge/discharge tests and electrochemical...
High-Performance, flexible, all-solid-state wire-shaped asymmetric micro-supercapacitors based on three dimensional CoNi2S4 nanosheets decorated-nanoporous Ni-Zn-P Film/Cu wire
, Article Journal of Physical Chemistry C ; Volume 123, Issue 35 , 2019 , Pages 21353-21366 ; 19327447 (ISSN) ; Naderi, L ; Sharif University of Technology
American Chemical Society
2019
Abstract
Demand increasing for next generation portable and miniaturized electronics has aroused much interest to explore microscale and lightweight energy storage devices. Herein, we demonstrate successful development of flexible wire-shaped micro-supercapacitors (micro-SCs) based on novel CoNi2S4/E-NZP film@Cu wire electrode. The etched Ni-Zn-P (E-NZP) film was synthesized by directly deposition of NZP film on Cu wire, followed by a chemical etching process. Alkaline etching treatment provides a micro- and mesoporous structure with high surface area and facilitates the penetration of electrolyte ions into the electrode matrix. Then, CoNi2S4 nanosheets as electroactive material are electrochemically...
Construction of a ternary nanocomposite, polypyrrole/fe-co sulfide-reduced graphene oxide/nickel foam, as a novel binder-free electrode for high-performance asymmetric supercapacitors
, Article Journal of Physical Chemistry C ; Volume 124, Issue 8 , 2020 , Pages 4393-4407 ; Kazeminezhad, I ; Naderi, L ; Shahrokhian, S ; Sharif University of Technology
American Chemical Society
2020
Abstract
The development of asymmetric supercapacitors requires the design of electrode construction and the utilization of new electroactive materials. In this regard, an effective strategy is the loading of active materials on an integrated 3D porous graphene-based substrate such as graphene foam (GF). Herein, we successfully designed and fabricated a novel ternary binder-free nanocomposite consisting of polypyrrole, Fe-Co sulfide, and reduced graphene oxide on a nickel foam electrode (PPy/FeCoS-rGO/NF) via a facile, cost-effective, and powerful electrodeposition method for application in high-performance asymmetric supercapacitors. The monolithic 3D porous graphene foam (GF) obtained by the facile...
Preparation and electrochemical performances of nanoporous/cracked cobalt oxide layer for supercapacitors
, Article Applied Physics A: Materials Science and Processing ; Vol. 117, issue. 4 , 2014 , pp. 2087-2094 ; ISSN: 09478396 ; Faraji, M ; Sharif University of Technology
Abstract
Nanoporous/cracked structures of cobalt oxide (Co3O4) electrodes were successfully fabricated by electroplating of zinc–cobalt onto previously formed TiO2 nanotubes by anodizing of titanium, leaching of zinc in a concentrated alkaline solution and followed by drying and annealing at 400 °C. The structure and morphology of the obtained Co3O4 electrodes were characterized by X-ray diffraction, EDX analysis and scanning electron microscopy. The results showed that the obtained Co3O4 electrodes were composed of the nanoporous/cracked structures with an average pore size of about 100 nm. The electrochemical capacitive behaviors of the nanoporous Co3O4 electrodes were investigated by cyclic...
Electrodeposited polyaniline on Pd-loaded TiO2 nanotubes as active material for electrochemical supercapacitor
, Article Journal of Electroanalytical Chemistry ; Volume 691 , 2013 , Pages 51-56 ; 15726657 (ISSN) ; Faraji, M ; Sharif University of Technology
2013
Abstract
PANI/Pd/TiO2NTs electrodes with highly porous structures and good capacitive characteristics were prepared by electrodeposition of polyaniline on palladium nanoparticles loaded TiO2 nanotubes. The loading of small palladium nanoparticles was carried out by sonochemical reduction of Pd+2 onto TiO2NTs and affected the ordered growth of PANI, reducing the charge transfer resistance and increasing surface area of PANI. The specific capacitance and the stability of electrode showed improvements. The results illustrated that the specific capacitance of these electrodes was around 1060 F g-1 in 1.0 M H2SO4 electrolyte as measured at a constant current of 2.0 A g-1, whereas it was 210 F g-1 for the...
A comparative study of sequentially layer-deposited and co-deposited Co-Mn oxides as potential redox capacitors
, Article Journal of Solid State Electrochemistry ; Volume 16, Issue 4 , April , 2012 , Pages 1561-1569 ; 14328488 (ISSN) ; Jafarzadeh, S ; Sharif University of Technology
2012
Abstract
Layers of cobalt and manganese oxides were co-deposited or deposited on top of each other or next to each other by potentiostatic method onto stainless steel substrate. Deposition potentials of 1 and -1 V for the anodic and cathodic depositions were employed. Specific capacitance values in the range of 38.5-78 F g -1 were found with cobalt oxide on top of manganese oxide having the lowest and manganese oxide on top of cobalt oxide having the highest capacitances. The usefulness of the electrodes was characterized by cyclic voltammetry, charge-discharge cycling, and electrochemical impedance spectroscopy in 2 M NaOH electrolyte for redox supercapacitor applications. The latter presented the...
Ternary nanostructures of Cr2O3/graphene oxide/conducting polymers for supercapacitor application
, Article Journal of Electroanalytical Chemistry ; Volume 823 , 2018 , Pages 505-516 ; 15726657 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Sharif University of Technology
Abstract
In this work, nanostructured composites of Cr2O3-graphene oxide (Cr2O3/GO) with conducting polymers; polyaniline (PANI) and polypyrrole (PPy) with the shape of cauliflower were synthesized via s simple and low cost one-step chronoamperometry method. The structures and morphologies of the resulting ternary nanocomposites were characterized by using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The electrochemical capacitive properties of the prepared nanocomposites were evaluated by using cycle voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The...
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) ; 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...
Iron‑vanadium oxysulfide nanostructures as novel electrode materials for supercapacitor applications
, Article Journal of Electroanalytical Chemistry ; Volume 818 , 2018 , Pages 157-167 ; 15726657 (ISSN) ; Shahrokhian, S ; Iraji Zad, Azam ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Iron‑vanadium oxysulfide (Fe-VO-S) nanostructures with different Fe:VO atomic ratios are synthesized by a facile and low cost electrochemical deposition method. The synthesis of the various samples is confirmed by the physicochemical characterizations such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). For different Fe-VO-S nanostructures, the correlation between the physicochemical and the electrochemical properties is investigated. It is found that the Fe:VO atomic ratio has an important effect on the structure and size of the resulted particles....
Ternary nickel cobalt iron sulfides ultrathin nanosheets grown on 3-D nickel nanocone arrays‑nickel plate current collector as a binder free electrode for fabrication of highly performance supercapacitors
, Article Journal of Electroanalytical Chemistry ; Volume 810 , 2018 , Pages 78-85 ; 15726657 (ISSN) ; Shahrokhian, S ; Hosseini, H ; Sharif University of Technology
Elsevier B.V
2018
Abstract
The design of 3-dimensional (3-D) nanostructured materials on the novel current collectors has recently considered as a promising strategy for developing high-performance supercapacitors. Herein, in the first step, a novel 3-D nickel nanocone arrays (NCAs) are synthesized on the surface of nickel plate (NP) by a one-step electrodeposition method without using any template (NCAs-NP). Then, a simple and efficient method is developed for fabricating ternary metal sulfides electrodes based on the electrodeposition of nickel cobalt iron sulfide (Ni-Co-Fe-S) ultrathin nanosheets on the surface of NCAs-NP. Taking advantages of the unique flower like structure of Ni-Co-Fe-S ultrathin nanosheets and...
Flexible free-standing vertically aligned carbon nanotube on activated reduced graphene oxide paper as a high performance lithium ion battery anode and supercapacitor
, Article Electrochimica Acta ; Volume 320 , 2019 ; 00134686 (ISSN) ; Abnavi, A ; Ghasemi, S ; Mohajerzadeh, S ; Sanaee, Z ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Here, controlled growth of vertically aligned carbon nanotubes (VACNTs) on free-standing porous activated reduced graphene oxide (a-rGO) paper was fabricated using plasma-enhanced chemical vapor deposition method. The electrochemical performance of prepared film was investigated to provide effective electrode for 3D flexible high-performance lithium-ion batteries (LIBs) and supercapacitors. The results revealed that the prepared electrode exhibited a high specific capacitance of 347 F/g at 0.5 A/g in 1 M KOH electrolyte, 60% more than non-activated rGO-paper (218 F/g). The VACNTs on a-rGO have increased the accessible surface area and acted as efficient electrical conducting paths, which...
Flexible and mechanically durable asymmetric supercapacitor based on nico-layered double hydroxide and nitrogen-doped graphene using a simple fabrication method
, Article Energy Technology ; Volume 7, Issue 5 , 2019 ; 21944288 (ISSN) ; Gilshteyn, E. P ; Melandsø Buan, M. E ; Sorsa, O ; Jiang, H ; Iraji zad, A ; Shahrokhian, S ; Nasibulin, A. G ; Kallio, T ; Sharif University of Technology
Wiley-VCH Verlag
2019
Abstract
A high-performing, lightweight, and flexible asymmetric supercapacitor (ASC) using NiCo-layered double hydroxide (NiCo LDH) supported on 3D nitrogen-doped graphene (NG) as a positive electrode and NG as a negative electrode is demonstrated. Highly conductive NG provides fast electron transfer and facilitates (dis)charging of NiCo LDH deposited on it. The composite electrode of NiCo LDH@NG exhibits a high specific capacitance of 1421 F g −1 at 2 A g −1 . Moreover, the as-obtained hybrid electrode shows an excellent rate capability with a specific capacitance of 1397 F g −1 at a high current density of 10 A g −1 , which is about 98% of the capacitance obtained at 2 A g −1 . The flexible ASC...
Polyphosphate-reduced graphene oxide on Ni foam as a binder free electrode for fabrication of high performance supercapacitor
, Article Electrochimica Acta ; Volume 296 , 2019 , Pages 130-141 ; 00134686 (ISSN) ; Asen, P ; Shahrokhian, S ; Ahadian, M. M ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Polyphosphate reduced graphene oxide on Ni foam (PPO-RGO/NF) is synthesized by varying weight ratios of Na5P3O10 (PO): graphene oxide (GO) with a simple, scalable and low cost method through freeze-drying of the PO-GO/NF followed by thermal treatment of the prepared electrodes. The resulting samples are characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), Brunauer-Emmett-Teller (BET), and raman spectroscopy methods. The results show that the weight ratio of PO:GO, considerably affect 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 ; 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...