Fatih Arican

Supercapacitor Behavior of Poly(Carbazole-EDOT) Derivatives/Multi-Walled Carbon Nanotubes, Characterizations and Equivalent Circuit Model Evaluations

Three new different comonomers of carbazole-EDOT derivatives had been previously synthesized and characterized in detail. In this study, electroactive materials were electropolymerized onto multi-walled carbon nanotube (MWCNT) modified glassy carbon (GC) electrode in 0.1 M sodium dodecyl sulphate (SDS) solution. The electrochemical impedance spectroscopic results of Nyquist, and Bode-magnitude and Bode-phase plots show that polymers/MWCNT composites possess good capacitive characteristics. P(Com2)/MWCNT/GCE systems specific capacitance was up to Sc = 132.6 F g−1 at the scan rate of 70 mV s−1 from the area formula, Eq. (1). Furthermore, P(Com2)/MWCNT composite had very rapid charge/discharge ability with specific capacitance of Sc = 75.23 F g−1 at DC potential of 0.3 V from Nyquist plot, and Sc = 90.53 F g−1 at the scan rate of 60 mVs−1 from charge formula, Eq. (2), which is important practical advantage. In addition, such composite had a good cycling performance and a wide potential window. Long-term stability of the capacitor was also tested by CV, and the results indicated that, after 500 cycles, the specific capacitance was still at ∼100.0%, ∼89%, and ∼97.0% of the initial capacitance for P(Com1)/MWCNT, P(Com2)/MWCNT, and P(Com3)/MWCNT, respectively. An equivalent circuit model of Rs(C1(R1(Q(R2W))))(CGCRGC) was obtained to fit the experimental and theoretical data. Solution resistance (Rs) and resistance from GCE decrease gradually. However, capacitance of film (C1), constant phase element (Q), and n values increase for P(Com1), P(Com2), and P(Com3)/MWCNT, respectively. Therefore, more homogeneous and less rough surface composite film was obtained by addition of MWCNT in the composite material.

Electrocoated Films of Poly(N-Methylpyrrole-co-2,2′-Bithitiophene-co-3-(Octylthiophene)), Characterizations, and Capacitor Study

N-Methylpyrrole (N-MPy), 2,2′-bithiophene (BTh), and 3-(Octylthiophene) (OTh) were electrocopolymerized in 0.2 M NaClO4/CH3CN on glassy carbon electrode (GCE). The resulting terpolymers of N-MPy, BTh and OTh in different initial monomer feed ratios such as [N-MPy]0/[BTh]0/[OTh]0 = 1/1/1 and 1/2/5 were characterized by cyclic voltammetry (CV), Fourier-transform infrared attenuated total reflectance spectroscopy (FTIR-ATR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and electrochemical impedance spectroscopy (EIS). The capacitive behaviors of the modified electrodes were defined via Nyquist, Bode-magnitude, Bode-phase, and Admittance plots. The equivalent circuit model of Rs(C dl1 (R 1 (QR 2 )))(C dl2 R 3 ) was performed to fit the theoretical and experimental data. The low-frequency capacitance (CLF) were obtained from initial monomer concentrations of 50 mM as CLF = ∼2.34 × 10−4 mFcm−2 for P(N-MPy), CLF = 5.06 × 10−4 mF cm−2 for P(BTh), CLF = 5.07 m F cm−2 for P(OTh), and CLF = ∼3.78 m Fcm−2 for terpolymer for [N-MPy]0/[BTh]0/[OTh]0 = 1/1/1. The terpolymer may be used as energy storage devices. GRAPHICAL ABSTRACT

Copolymer formation of 4-vinylbenzyl-9H-carbazole-9-carbodithioate and ethylenedioxythiophene and capacitive behavior

In this study, first, a new monomer of 4-vinylbenzyl 9H-carbazole-9-carbodithioate (VBzCzCT) was chemically synthesized and characterized using Fourier transform infrared (FTIR) reflectance, proton nuclear magnetic resonance (1H NMR), and carbon nuclear magnetic resonance (13C NMR) spectroscopies. Second, VBzCzCT and 3,4-ethylenedioxythiophene (EDOT) monomers were electrocopolymerized (VBzCzCT-co-EDOT) in 0.1 M sodium perchlorate (NaClO4)/acetonitrile (CH3CN) on glassy carbon electrode (GCE) using cyclic voltammetry (CV). Third, the best deposition conditions on the electroactivity of the modified homopolymers and copolymer were studied and characterized using different techniques such as CV, FTIR-attenuated total reflectance, scanning electron microscopy–energy dispersion x-ray analysis, and electrochemical impedance spectroscopy (EIS) analysis. The specific capacitance (C sp) of poly(VBzCzCT) (P(VBzCzCT)) was obtained as 20.5 mF cm−2. However, the C sp of P(VBzCzCT-co-EDOT)/GCE was obtained as 45.5 mF cm−2. There is an important improvement in the capacitance value of copolymer formation. The C sp value increases more than twice from P(VBzCzCT) to copolymer. The highest double layer capacitance (C dl = approximately 27.5 mF cm−2) was obtained for P(VBzCzCT-co-EDOT) and P(EDOT) compared with P(VBzCzCT) (C dl = approximately 8.28 mF cm−2. Finally, simulation graphs of Nyquist, Bode-magnitude, and Bode-phase plots were given for homopolymers and copolymer for the electrical equivalent circuit model of R s(Q 1(R 1(C 1(R 2(C 2(R 3 · W))))))(C 3 R 4). The EIS results of P(VBzCzCT), P(EDOT), and P(VBzCzCT-co-EDOT) might be studied as promising active electrode materials for (super)capacitor evaluations.

A novel synthesis of 3,6-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-9-tosyl- 9H-carbazole

Abstract 3,6-bis(2,3-dihydrothieno [3,4-b][1,4]dioxin-5-yl)-9-tosyl-9H-carbazole (EDOTTsCz) was synthesized and electrochemically polymerized on glassy carbon electrode (GCE) in 0.1 M tetrabutyl ammonium tetrafluoroborate (NB4BF4)/acetonitrile (CH3CN). Alternating copolymer was formed by CV method. Modified polymer electrode was characterized by Fourier transform Infrared Spectroscopy-Attenuated Transmission Reflectance (FTIR-ATR), Cyclic voltammetry (CV), Scanning electron microscopy-Energy dispersive X-ray analysis (SEM-EDX), Atomic force microscope (AFM) and Electrochemical impedance spectroscopy (EIS). Capacitive behaviors of the modified GCE were defined via Nyquist, Bode-magnitude, Bode-phase and Capacitance plots. A modified copolymer electrode provides enhanced capacitance evaluation, which may results in performance in energy storage devices.

Electrochemical copolymerization of N -methylpyrrole and 2,2′-bithitiophene; characterization, micro-capacitor study, and equivalent circuit model evaluation

AbstractN-methylpyrrole (N-MPy) and 2,2′-bithiophene (BTh) were electrocopolymerized in 0·2 M acetonitrile–sodium perchlorate solvent–electrolyte couple on a glassy carbon electrode (GCE) by cyclic voltammetry (CV). The resulting homopolymers and copolymers in different initial feed ratios of [N-MPy]0/[BTh]0= 1/1, 1/2, 1/5 and 1/10 were characterized by CV, Fourier-transform infrared reflectance attenuated transmittance (FTIR–ATR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and electrochemical impedance spectroscopy (EIS). The capacitive behaviours of the modified electrodes were defined via Nyquist, Bode-magnitude, Bode-phase and admittance plots. The equivalent circuit model of R(C(R)(QR)(CR)) was performed to fit theoretical and experimental data. The highest low-frequency capacitance (CLF) were obtained as CLF = ∼ 1·23 × 10−4 mF cm−2 for P(N-MPy), CLF = ∼ 2·09 × 10−4 mF cm−2 for P(BTh) and CLF = ∼ 5·54 × 10−4 mF cm−2 for copolymer in the inital feed ratio of [N-MPy]0/[BTh]0= 1/2. Figure. Bode - magnitude and phase plot for a) poly(N-MPy), [N-MPy]0 = 20 mM, inset: Equivalent circuit model of R(CR)(QR)(CR), b) poly(BTh), [BTh]0 = 20 mM, c) poly(N-MPy-co-BTh), [N-MPy]0/[BTh]0 = 1/5 electro-coated on CFME