Complex electrical impedance and dielectric spectroscopy of Na+-conducting PEO/PVP/NaIO4 solid polymer electrolyte with incorporated Graphene Oxide nanoparticles

Being of significant interest as electrolytic materials for mini-mobile energy storage devices, we have studied solid-state polymer-based electrolytic systems - nanocomposites, in particular, NaIO4 salt-complexed poly(ethylene oxide) (PEO)/polyvinyl pyrrolidone (PVP) polymer blends doped with Graphene Oxide (GO) nanoparticles-nanosheets. The GO monolayer average size and thickness were 5 μm and 2 nm, respectively. In the PEO/PVP polymer blend, the PEO:PVP ratio was 70:30 weight percent (wt.%), the concentration of the salt sodium metaperiodate NaIO4 was 10 wt.%. The GO nanosheets were dispersed with concentration of 0; 0.2; 0.4 and 0.6 wt.%. Thin films (150 μm) of GO/PEO/PVP/NaIO4 Na+ ion-conducting nanocomposites were produced by solution casting technique. They were studied by complex electrical impedance and dielectric spectroscopy in the frequency range 0.1 Hz - 1 MHz of the applied electric field. The ion conductivity, the complex dielectric function, dielectric loss and AC conductivity of GO/PEO/PVP/NaIO4 at various concentration of GO were analyzed, and the effect from the GO nanofillers was estimated. The results from dielectric analysis were interrelated to the macroscopic properties and ionic conductivity of the studied nanocomposite solid polymer electrolytes. At concentration 0.6 wt.% GO, the enhancement of dielectric permittivity of GO-doped PEO/PVP/NaIO4 can reach a factor of 60, as compared to undoped PEO/PVP/NaIO4 electrolyte. The electrical conductivity and dielectric properties of the produced Na+ ion-conducting nanocomposites with GO nanodopants are promising for ion electrolytic applications and energystorage devices.