In this work, we introduce a method based on impedance spectroscopy and the equations developed to evaluate, with a good degree of accuracy, the number density, mobility and diffusion coefficient of mobile ions. Nyquist plots of electrolytes based on poly(acrylonitrile) or PAN and methyl cellulose (MC) incorporated with lithium bis(oxalato)borate have been established from impedance measurements. Equivalent circuits based on a resistor and "leaky capacitor(s)" have been determined and the relevant impedance equations derived. The values of the parameters required in the equation are obtained from the Nyquist plots and the parameters that cannot be obtained from the respective plots have been obtained by trial and error in order to fit the Nyquist plots. The transport parameters are calculated using the developed equations and the results have been compared with those obtained from the broadband dielectric response (BDR) method. Finally, Fourier transform infrared (FTIR) spectroscopy has been used to verify the results obtained from the two approaches at room and elevated temperatures.

Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorphous and crystalline structures of film were investigated by X-ray diffraction (XRD). The surface morphology of samples was examined by scanning electron microscopy (SEM). The composition and complex formation of films were characterized by Fourier transform infrared (FTIR) spectroscopy. The conductivity of the PAA-ZnA films was determined by electrochemical impedance spectroscopy. According to the XRD and FTIR analyses, all electrolyte films were in amorphous state and the existence of interaction between Zn 2+ cations and the PAA structure confirms that the film was successfully prepared. The SEM observations reveal that the electrolyte films appeared to be rough and flat with irregularly shaped surfaces. The highest ionic conductivity (σ) of 1.82 × 10 − 5 Scm −1 was achieved at room temperature (303 K) for the sample containing 10 wt % ZnA.

No abstract

No abstract

No abstract