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Synthesis of MXene/Polyaniline Composite as an Electrode Material for Supercapacitors
, M.Sc. Thesis Sharif University of Technology ; 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...
Preparation of New Titanium Nitride-Carbon Nanocomposites and Evaluation of their Electrocatalytic Behavior
, Ph.D. Dissertation Sharif University of Technology ; Ghorbani, Mohammad (Supervisor) ; Dolati, Abolghasem (Supervisor)
Abstract
Titanium nitride-carbon nanocomposites are synthesized by the reaction of TiCl4 and NaN3 in supercritical benzene medium that also serves as a carbon source. In order to improve the crystallinity of the as-prepared precursor (SI), it is further heat-treated at 1000 ˚C for 3-10 h using anhydrous ammonia and UHP nitrogen atmospheres at 1000 ˚C (SIII-SV). Moreover, to improve electrochemical behavior, the synthesized nanocomposite (SIV) is modified with Pt nanoparticles using a polyol process. For better understanding of synthesized catalyst nature and justifying their variant ORR activity several analyses are done. X-ray diffraction (XRD), Raman spectrum, field emission scanning electron...
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...
Elevated-temperature behaviour of LiNi0.5Co0.2Mn0.3O2 cathode modified with rGO-SiO2 composite coating
, Article Journal of Alloys and Compounds ; Volume 843 , 2020 ; Khalili Azar, M ; Esmaeili, M ; Tanhaei, M ; Dolati, A ; Hosseini H, S. M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
An intense decrease in cycling performance and safety is a challenge for elevated temperature application of LiNi0.5Co0.2Mn0.3O2 (NCM) cathode material. In this paper, effect of two types of nano-coatings on improvement of elevated temperature performance of NCM cathode material has been investigated. One of the coatings contains SiO2 nanoparticles and the other one contains composite of reduced graphene oxide and SiO2 nanoparticles (rGO-SiO2). The coatings were fabricated by a facile wet chemical method. The SiO2 coated cathode material showed an excellent elevated temperature cycling stability, however, a decrease in discharge capacity and rate capability of this sample was observed. On...