Browsing by Author "Saaid, Farish Irfal"

Now showing 1 - 2 of 2

Hexanoyl chitosan/ENR25 blend polymer electrolyte system for electrical double layer capacitor
(2019-03-01)
Winie, Tan
;
Jamal, Asheila
;
Saaid, Farish Irfal
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
Single salt polymer electrolytes based on hexanoyl chitosan-ENR25 were prepared by employing LiN (CF3SO2)(2) or LiCF3SO3 as the doping salt. Elastic property of hexanoyl chitosan was enhanced with the incorporation of ENR25. DSC studies revealed immiscibility of hexanoyl chitosan and ENR25, and dissolution of salt was favored in ENR25 phase. Conductivity enhancement was observed in the blends as compared with the neat hexanoyl chitosan. The maximum conductivities achieved for LiCF3SO3- and LiN (CF3SO2)(2)-comprising electrolyte systems were 1.6 x 10(-8) and 5.0 x 10(-7) S cm(-1), respectively. Deconvolution of spectra bands in the v(as) (SO2-) mode of LiN (CF3SO2)(2) and v(s) (SO3-) mode of LiCF3SO3 has been carried out to estimate the relative percentage of free ions and associated ions. The findings were in good agreement with conductivity results. Electrical double layer capacitor (EDLC) was fabricated with hexanoyl chitosan/ENR25 (90:10)-LiN (CF3SO2)(2)-EmImTFSI electrolyte and activated carbon-based electrodes. The conductivity and electrochemical stability window of hexanoyl chitosan/ENR25-LiN (CF3SO2)(2)-EmImTFSI were similar to 10(-6) S cm(-1) and 2.7 V, respectively. The performance of the EDLC was analyzed by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). From GCD, the specific capacitance of EDLC was 58.0 F g(-1) at 0.6 mA cm(-2). The specific capacitance was found to decrease with increasing current density.
The synergistic effect of iron cobaltite compare to its single oxides as cathode in supercapacitor
(1970-01-01)
Saaid, Farish Irfal
;
Arsyad, Akmal
;
Azman, N. S. H.
;
Kumar, Amit
;
Yang, Chih-Chieh
Mixed transition metal oxides have attracted great attention in supercapacitors applications due to their better electrochemical performance than their single oxides. In this work, iron cobaltite (FeCo2O4) and its single metal oxides i.e. iron oxide (Fe2O3) and cobalt oxide (Co3O4) were synthesized by a simple hydrothermal process. The structural, spectroscopic and morphological properties were studied using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field-emission scanning electron microscope (FESEM). XRD and FTIR results show the composition of the products. The obtained iron oxide was alpha-Fe2O3. FESEM images show that FeCo2O4 and its single metal oxides exhibit different morphology even though they were synthesized via similar method. The electrochemical properties of the alpha-Fe2O3, Co3O4 and FeCo2O4 electrodes were examined by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) in a 6 M KOH electrolyte solution. At comparable current density, the FeCo2O4 electrode has the highest specific capacitance (C-sp), followed by Co3O4 and alpha-Fe2O3. An asymmetric FeCo2O4/KOH/GO supercapacitor was fabricated. The supercapacitor exhibits maximum energy density of 14.5 Wh kg(-1) and maximum power density of 2177 W kg(-1). It demonstrates 60% rate capability after 1000 continuous charge-discharge cycles at 1 A g(-1).