Electrochemical Impedance and Dielectric Spectroscopy Study of TiO2-Nanofilled PEO/PVP/NaIO4 Ionic Polymer Electrolytes

We have experimentally investigated the ion-conducting and dielectric properties of nanocomposite ion-conductive polymer electrolytes based on two-polymer blend of poly(ethylene oxide) (PEO) and polyvinyl pyrrolidone (PVP), with added sodium metaperiodate (NaIO4) at concentration of 10 wt%. The polymer-ion complexes PEO/PVP/NaIO4 are doped with small amount (up to 3 wt%) TiO2 nanoparticles of average size ~ 10 nm. Chemically-stable free-standing thin films (150 µm) of the synthesized PEO/PVP/NaIO4/TiO2 solid-state polymer electrolyte material are formed by using conventional solution-cast technique. The electrical and dielectric properties of these nanocomposites are studied by complex electrical impedance and dielectric spectroscopy over the frequency range 1 Hz – 1 MHz. The ionic conductivity of TiO2-nanofilled PEO/PVP/NaIO4/TiO2 is determined as dependent on the concentration of the included TiO2 nanoparticles. The obtained results indicate that both the Na+-ion conductivity and the dielectric function of PEO/PVP/NaIO4/TiO2 nanocomposite electrolytes are enhanced upon addition of TiO2 nanoparticles. Thus, the produced NaIO4 salt-complexed TiO2-nanofilled ionic polymer electrolytes are attractive for use in sodium ion secondary batteries, electrochemical applications, as well as in organic electronics.