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    Öğe
    Carbon nanofiber/poly(tetrahydro[1,4] dioxino[2,3-b] thieno[3,4-e][1,4] dioxine) binder-free composite redox-active electrode for electrochemical energy storage applications
    (Royal Soc Chemistry, 2017) Yigit, Deniz; Soysal, Furkan; Gungor, Tugba; Cicek, Burhanettin; Gullu, Mustafa
    We report the preparation and supercapacitive properties of a novel composite electrode material based on carbon nanofiber (CNF) and poly(tetrahydro[1,4] dioxino[2,3-b] thieno[3,4-e][1,4] dioxine) (PTDTD) for electrochemical energy storage applications. The CNF/PTDTD composite electrode was directly prepared by electrodeposition of PTDTD on the CNF coated substrate without any binder or conductive additives. The symmetric solid-state supercapacitor device was assembled by using these CNF/PTDTD composite electrodes. In addition, CNF/CNF and CNF/poly(3,4-ethylenedioxythiophene) (PEDOT) symmetric supercapacitor devices were also fabricated to make a detailed performance comparison. The electrochemical characteristics of all supercapacitor devices were comprehensively evaluated by CV, GCD and EIS measurements. The CNF/PTDTD composite electrodes delivered a maximum specific capacitance of 332 F g(-1), energy density of 166 W h k g(-1), power density of 4.9 kW kg(-1) and an excellent cycling stability with 89% capacitance retention after 12 500 cycles at 2 mA cm(-2) current density while CNF/PEDOT electrodes were able to reach a specific capacitance of 254 F g(-1), energy density of 128.8 W h kg(-1) and power density of 5.45 kW kg(-1) in those supercapacitor devices. These results confirmed that PTDTD has significant potential to be a good alternative redox-active material and CNF/PTDTD composite structure is a promising candidate for supercapacitor applications.
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    Öğe
    Poly(thieno[3,4-b][1,4] dioxine) and poly([1,4] dioxino[2,3-c] pyrrole) derivatives: p-and n-dopable redox-active electrode materials for solid state supercapacitor applications
    (Elsevier, 2013) Yigit, Deniz; Gungor, Tugba; Gullu, Mustafa
    We report the synthesis and supercapacitive properties of novel poly(2,3,4a, 9a-tetrahydro[ 1,4] dioxino[2,3-b] thieno[3,4-e][1,4] dioxine) (pTDTD) and poly(7-butyl-3,4a, 7,9a-tetrahydro- 2H-[1,4] dioxino[2',3': 5,6][1,4] dioxino[2,3-c] pyrrole) (pTDDP) as redox-active electrode materials for supercapacitor applications. At first, new thiophene and pyrrole monomers containing of fused two 1,4-dioxane rings were successfully synthesized and their conducting polymers were prepared electrochemically on a stainless steel (SS) electrode. Symmetric and asymmetric solid state pseudocapacitor devices were fabricated in order to evaluate supercapacitive performances of newly designed pTDTD and pTDDP. The SS electrodes modified with pTDTD and pTDDP were used as an anode material against pEDOT coated SS cathode in asymmetric devices and as both anode and cathode material in symmetric devices. Capacitive behaviors and performances of the devices were tested by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) techniques. In symmetric devices, pTDTD provided a specific capacitance of 260 F/g and specific energy of 288Wh/kg, while the pTDDP was found to be not a suitable redox-active electrode material for pseudocapacitor applications. (C) 2013 Elsevier B.V. All rights reserved.