Search

The electrochemical efficiency of a supercapacitor highly depends on the electrochemical properties of electrodes used in its fabrication. Herein, we synthesize highly efficient reduced graphene oxide (rGO) electrodes by tuning the concentration of polyvinylidene fluoride (PVDF) as a binder through solvent evaporation. The structural, morphological, and electrochemical properties of rGO/PVDF composite electrodes are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), Raman spectroscopy, Scanning electron microscopy (SEM), and Transmission scanning electron microscopy (TEM), Cyclic voltammetry (CV), Galvanostatic charge-discharge analysis (GCD), and Electrochemical impedance spectroscopy (EIS). The rGO/PVDF composite electrodes possess an elliptical-shaped voltammogram with high symmetry, and quasi-triangular-shaped GCD curves indicating the ideal supercapacitor characteristic with excellent charging-discharging stability. The highest specific capacitance of 307 F/g at a scan rate of 100 mV/s and 1080 F/g at a current of 0.1 mA was obtained for the PvG2 electrode. The symmetric electrical double layer (EDLC) supercapacitor fabricated using the PvG2 electrode has an elliptical-shaped voltammogram with high symmetry, which indicates ideal supercapacitor behaviour. The highest power and energy densities gained for the supercapacitors are 2400 W/Kg and 24.1 Wh/Kg at 0.02A and 0.003 A respectively. Furthermore, approximately 78.9 % of capacitance retention and 91.03 % coulombic efficiency were observed for supercapacitors after 5000 cycles. 2022 Elsevier Ltd This work was financially supported by the APJ Abdul Kalam Technological University (KTU), Thiruvananthapuram (KTU proceedings No. 4/1654/2019). Scopus

The natural rubber/graphene quantum dots (GQDs) nanocomposites were prepared and their properties have been studied. Graphene oxide prepared via modified Hummer’s method was the precursor used to synthesis graphene quantum dots. The two-roll mill was used for the compounding of the natural rubber/graphene quantum dot (NR/GQD) nanocomposites. The nanocomposites are characterized using UV–visible Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM), X-ray Diffraction Analysis (XRD), Thermogravimetric Analysis (TGA). The mechanical and diffusion properties of the natural rubber/graphene quantum dot (GQDs) nanocomposites were also investigated. The TEM analysis revealed that GQD has tiny spherical shaped morphology with an average size value of 5 nm. The FTIR and XRD studies clearly showed the strong interaction between GQDs and NR and the peak at 8.490 in the diffractogram of nanocomposites indicates the uniform distribution of GQDs in matrix of NR. The incorporation of 1phr of GQD shows a 30%, 13% and 23% of enhancement in respective tensile strength, elongation at break and young’s modulus of the NR/GQD nanocomposite compared to that of pure natural rubber. The study found that the incorporation of GQDs into the natural rubber matrix dramatically increased the mechanical and thermal properties of the of NR. The nanocomposite with 1.5 phr of GQD showed higher thermal stability and is ascribed to the uniform dispersion and interaction of GQD in the NR matrix. The GQD will act as a protective barrier and thus it arrests the thermal decomposition by absorbing the heat that liberated in the matrix.

Nanocomposites with multifunctional properties are of great interest as they meet the needs of the developing industrial and engineering fields. The present study focus on the development of multifunctional elastomeric nanocomposites with exfoliated graphite (EG) as the reinforcing content and the speciality material fluoroelastomer as the polymer matrix. Morphological analysis of the nanocomposites in terms of TEM, AFM and SEM were done to look at the polymer-filler interactions which in turn lead to the property enhancement. The dispersion of the EG in the nanoscale which resulted in the property enhancement is clear from the TEM images. Nanocomposites exhibited improved thermal stability and higher mechanical strength by the addition of 12 phr of EG nanofiller. Moreover the dielectric performance of the nanocomposites was also enhanced by the addition of conductive EG nanofiller and the nanocomposites showed higher dielectric constant value and AC conductivity with lower dielectric loss. In addition to this the solvent transport features of the nanocomposites were also analyzed to reveal the reinforcement effect of the nanofiller and the effective polymer-filler interactions.

The rising energy consumption in today's world need electrochemical devices with excellent energy storing efficiency. Supercapacitors are considered as incredible energy-storing devices due to high power density, longevity, exceptional charge/discharge cycling stability, and low cost. The electrochemical performance of the supercapacitors absolutely relies upon the choice of its establishing parts like electrodes, binder, separator, electrolyte, and current collector; and its manufacture strategy. The part of polymers in this field is inescapable and has a background marked by many years. This review deliberately extends the part of polyvinylidene fluoride (PVDF); its copolymer and nanocomposites as a binder, separator, electrolyte, and piezoelectric generator in the development of supercapacitors. Polyvinylidene fluoride is a semi-crystalline polymer and the second-biggest fluoropolymer underway. It displays great mechanical properties, high dielectric consistent, wettability, and excellent thermal and chemical strength. Today, PVDF is quite possibly the most requesting polymers because of its self-polarizing capacity under the electric field. The piezoelectric, pyroelectric, and ferroelectric properties of PVDF pulls into the consideration of researchers and specialists who are working in the development of self-charging supercapacitors and other energy reaping and storing gadgets. This review succinctly uncovers the future viewpoint for the advancement of PVDF-based self-powering electronic gadgets.

The influence of poly(vinylidene fluoride) (PVDF) as a binder on enhancing the electrochemical performance of graphite (G) electrodes was studied. The structural analysis of prepared composite electrodes was studied using X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The electrochemical properties of the PVDF/Graphite composite electrodes were studied using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The SEM images of graphitic electrodes proved the binding ability of PVDF. PVDF provide a compact arrangement to the graphitic electrodes. The electrochemical analysis showed that among graphitic electrodes, PVDF with 5 g graphite i.e., PvG5 electrode has an ideal capacitor behaviour with good cycling stability and low internal resistance. The highest specific capacitance of 16.2 F/g at a scan rate of 10 mV/s and 13.11 F/g at a current of 0.00001 A was obtained for the PvG5 electrode. Furthermore, approximately 87% of capacitance retention was observed for PvG5 electrode after 1000 cycles. The specific surface area calculated from BET analysis for the PvG5 electrode is 640.2 m2/g which is 30-fold compared to pure graphite. The PvG5 electrode possess good electrochemical properties compared to pristine graphite and it is a promising electrode of electrical double layer capacitor (EDLC).