Role of nano-capacitor on dielectric constant enhancement in PEO:NH4SCN:xCeO2 polymer nano-composites: Electrical and electrochemical properties

Solution casting technique has been successfully employed to prepare nano-composite films. Various weight ratios of cerium oxide (CeO2) nanoparticle were added to a PEO:NH4SCN:xCeO(2) polymer matrix to enhance the ionic conductivity at ambient temper-ature. The electrical and electrochemical properties of the composite electrolyte systems have been investigated using impedance, dielectric properties (epsilon*, tan delta, and M*), transfer number measurement (TNM), linear sweep voltammetry (LSV), and cyclic voltammetry (CV) techniques. The highest ionic conductivity of similar to 8.57 x 10(-4) S/cm is obtained for the system incorporated with 3 wt.% of CeO2 filler. This study presented a new approach and the com-plex permittivity confirmed that the real part value of dielectric constant (epsilon') for all samples has found to be much higher than the imaginary part (epsilon ''') value. The appearance of the peaks at a characteristic frequency in the loss tangent indicates the existence of relaxation. Low dielectric modulus is observed for 3 wt.% of CeO2 incorporated. The TNM measurements confirmed the ionic conductivity of NCSPEs and ion transport t(ion) of films have been found to be 0.84, 0.96 and 0.92 for 1 wt.%, 3 wt.%, and 5 wt.% of CeO2, respectively. The system incorporated with 3 wt.% of CeO2 has discovered to be electrochemically stable up to 1.4 V. From the CV analysis it is noticeable that the energy storage mechanism of the EDLC is a combination of double-layer capacitance and pseudo capacitance. A value of 88.9 F/g is achieved at 20 mV/s. (C) 2020 The Author(s). Published by Elsevier B.V.