Binary nanocomposites of reduced graphene oxide and cobalt (II, III) oxide for supercapacitor devices

In this study, a simple and one-step cost-effective preparation of rGO/Co3O4 nanocomposite was given out in different monomer concentrations of [rGO]o/[Co3O4]o= 1:1; 1:2; 1:5 and 1:10. The electroactive materials were characterized by many techniques, such as FTIR-ATR, XPS, TGA-DTA, Raman, BET surface analysis, GCD, SEM-EDX, XRD, TEM, CV, and EIS analysis. A symmetric supercapacitor applying rGO/Co3O4 nanocomposite as positive and negative electrodes was taken in the potential window between 0.0 and 0.8 V as the highest specific capacitance of Csp= 115.35 F×g-1 at 2 mV×s-1 for [rGO]o/[Co3O4]o= 1:2. Furthermore, the highest energy (E) and power densities (P) were obtained as E= 20.16 Wh×kg-1 at 40 mA and P= 26.140 kW×kg-1 at 10 mA for [rGO]o/[Co3O4]o= 1:2 by GCD method, respectively. As a result, rGO/Co3O4 nanocomposite at different monomer concentrations showed an easy synthesis, a sustainable approach, and a high electrochemical performances for energy storage devices. © 2021 Informa UK Limited, trading as Taylor & Francis Group

Reduced graphene oxide/Titanium oxide nanocomposite synthesis via microwave-assisted method and supercapacitor behaviors

In this paper, graphene oxide (GO) was firstly synthesized by modification of Hummers method from the literature. Secondly, reduced graphene oxide (rGO)/Titanium oxide (TiO2) nanocomposites were synthesized with different wt/wt % of GO/TiO2 (1:1; 1:2; 1:5 and 1:10) by microwave-assisted method. By treating GO and GO/TiO2 nanocomposites in a microwave oven, reduced graphene oxide (rGO) and rGO/TiO2 materials could be obtained within power of 180 Win 10 min. The weight ratio of rGO and TiO2 was used to obtain the optimum conditions for nanocomposite materials. The rGO/TiO2 nanocomposite active materials were characterized by cyclic voltammetry (CV), Fourier-transform infrared - Attenuated total reflectance (FTIR-ATR), scanning electron microscopy-energy dispersion X-ray (SEM-EDX), thermogravimetry (TGA), differential thermal analyzer (DTA) and electrochemical impedance spectroscopy (EIS) analysis. Thirdly, supercapacitors were fabricated as a symmetric device with two electrode configuration. The device performances were tested by CV, galvanostatic constant current (CC), and EIS measurements. TGA analysis indicated that the thermal stability of the nanocomposites improved from rGO (40% at 892.8 degrees C) to nanocomposite as the initial feed ratio of [GO](o)/[TiO2](o) = 1/10 as (94% at 949.3 degrees C) increased. The result show that the as-prepared symmetrical rGO/TiO2 nanocomposite on the two-electrode system displays very high specific capacitance of 524.02 F/g at 2 mV/s for [GO](o)/[TiO2](o) = 1/5 with a high energy density of E = 50.07 Wh/kg at 2 mV/s for [GO](o)/[TiO2](o) = 1/1 and high power density of P = 58.6 kW/kg at a the scan rate 1000 mV/s for [GO](o)/[TiO2](o) = 1/1. Additionally, the symmetric electrode shows good cycling stability with a retention value of 6.6% for [GO](o)/[TiO2](o) = 1/1 after 1000 cycles. These good results suggest us that rGO/TiO2 nanocomposite which is obtained by microwave-assisted method has a great potential as an electrode material for supercapacitor applications. The equivalent circuit model of R-s(C-dl(RctW)) was used to explain parameters of solution resistance, double layer capacitance (Cdl), charge transfer resistance (R-ct), Warburg impedance (W). Theoretical and experimental values support with each other. (C) 2017 Elsevier B.V. All rights reserved

Reliability of electrode materials for supercapacitors and batteries in energy storage applications: a review

Supercapacitors and batteries are among the most promising electrochemical energy storage technologies available today. Indeed, high demands in energy storage devices require cost-effective fabrication and robust electroactive materials. In this review, we summarized recent progress and challenges made in the development of mostly nanostructured materials as well as fabrication routes for energy storage devices. Indeed, we systematically sorted out the design principles of electrode materials such as lithium-ion, lead-acid, lithium-sulfur, nickel-cadmium, nickel-metal hydride, and sodium-ion for rechargeable batteries electrode and supercapacitors (SCs) electrode materials following by systematic discussions on electric double-layer capacitors, pseudocapacitors, and hybrid SCs behavior. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature

rGO/CuO/PEDOT nanocomposite formation, its characterisation and electrochemical performances for supercapacitors

Supercapacitor properties of rGO, CuO, PEDOT and rGO/CuO at [rGO](o)/[CuO](o) = 1:1; 1:1.5; 1:2 and rGO/CuO/PEDOT nanocomposite at [rGO](o)/[CuO](o)/[EDOT](o) = 1:1:1; 1:1:3; 1:1:5 were investigated using chemical reduction of GO and in-situ polymerisation process. SEM-EDX, HRTEM, BET surface area analysis confirm the nanocomposite formations. Nanocomposite materials are also analysed through FTIR-ATR, Raman, TGA-DTA, GCD, CV and EIS. The highest specific capacitance of C-sp = 156.7 F/g at 2 mV/s is determined as rGO/CuO/PEDOT at [rGO](o)/[CuO](o)/[EDOT](o) = 1:1:5. In addition, two-electrode supercapacitor device for rGO/CuO/PEDOT at [rGO](o)/[CuO](o)/[EDOT](o) = 1:1:5 are found to provide a maximum specific energy (E = 14.15 Wh/kg at 20 mA) and specific power (P = 24730 W/kg at 50 mA), electrical serial resistance (ESR = 13.33 omega) with good capacity retention after 3000 cycles. An equivalent circuit model of LR1(CR2)(QR3) is proposed to interpret the EIS data. The supercapacitor performance of the rGO/CuO/PEDOT nanocomposite electrode indicates the synergistic effect of hybrid supercapacitors.Namik Kemal Uni., Scientific Research Project UnitNamik Kemal University [NKUBAP.01, YL.18.151]This work was supported by Namik Kemal Uni., Scientific Research Project Unit [grant number: NKUBAP.01.YL.18.151]