Polymer composite solid electrolytes: structural and electrical studies

Abstract

Solid electrolytes are a class of solids which show high ionic conductivities despite their rigid structure. These materials are characterised by their high ionic conductivities with a similar order of magnitude to that usually found in molten salts. Composite solid electrolytes are prepared by mixing two or more conducting solids. Polymer solid electrolytes refer to the polymeric systems which enable efficient ion migration even in the solid state – comparable to that in the solution state. Polymer electrolytes are ion-conducting materials with values of ionic conductivity as high as 10−4S/cm or more. This research studied polymer-based composite solid electrolytes, where polyaniline doped with sodium sulfate was used. Different compositions based on sodium sulfate concentrations ranging from 25 to 90% (by weight) were studied over the temperature range of 50–300°C by using techniques such as scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and impedance spectroscopy. The observed conductivities lie in the range of 10−4–10−7 S/cm. Maximum conductivity was observed for the composition 50:50, which showed an activation energy of 0·12 eV.