No abstract

No abstract

The present work in on the successive ionic layer adsorption and reaction (SILAR) mediated synthesis and study of variations in electrochemical behavior of PPy-Cu(OH)2 hybrid electrodes with dip time. In the aqueous route preparation, 0.1 m pyrrole, 0.1 m CuSO4 dissolved in acidified water (using 0.5 m H2SO4) and H2O2 (30 wt %) were used as initial ingredient sources. The peaks observed in the X-Ray diffraction (XRD) pattern of the electrode at 2θ=21.500 oriented along the <110> planes closely match with the peaks of Cu(OH)2 as per JCPDS data card no. 42-0638 indicating the existence of triclinic Cu(OH)2 in the hybrid. The characteristic peak at 1559 cm−1 in the Fourier transform infrared (FTIR) spectrum due to pyrrole ring vibrations confirms the existence of PPy in the hybrid. Energy-dispersive X-ray (EDX) analysis shows the occurrence of C, N, O and Cu in the electrode material which substantiates the formation of the hybrid. The scanning electron microscopy (SEM) images of electrodes with optimum dip time (20 s) in pyrrole show networks of interconnected nanostructures. The specific capacitance increases with the dip time in the source solutions. The electrode prepared with optimum dip time in pyrrole has produced the maximum values of specific capacitance (SC), specific energy (SE) and specific power (SP) as 127.04 F/g, 44.16 Wh/kg and 30 kW/kg, respectively, when analyzed in 0.5 m H2SO4. Impedance study of the electrode explains the mixed capacitive nature and the maximum values of solution resistance (Rs), charge transfer resistance (Rct) and Warburg impedance (Rw) are 1.35 Ω, 143.4 Ω and 2.05 Ω, respectively.

The rate of polymerization decides growth and hence electrochemical properties of the electrodes of conducting polymers synthesized by SILAR method are affected by molar concentration of the precursors. Present work describes the effect of molar concentration of Pyrrole monomer on the rate of polymerization and hence the electrochemical performance of highly pristine PPy flexible electrodes. 304 grade flexible stainless steel strips were coated with the PPy using aqueous solutions of 0.025M, 0.05 M and 0.1M pyrrole in 0.5 M H2SO4 separately and 30% H2O2. XRD patterns substantiate the formation of amorphous PPy. The peak at 1560 cm−1 in FTIR confirms the formation of polypyrrole. SEM images of the FEs prepared using different molar concentration shows gradual superficial growth. All FEs were electrochemically analyzed for their supercapacitive performance by the electrochemical techniques like cyclic voltammetry, galvanostatic charge discharge study and electrochemical impedance spectroscopy. It was found that, the specific capacitance increases with molar concentration of pyrrole. The pristine PPy FEs prepared with 0.1 M Pyrrole exhibit specific capacitance as high as 899.14 Fg-1 at 5 mVs-1 in 0.2 M Na2SO4.

No abstract