Mechanism of ionic conductivity in poly(ethylene glycol 400)/(MgCl2)x polymer electrolytes: studies based on electrical spectroscopy

In this paper, eight solvent-free polymer electrolytes PEG400/(MgCl2)x (0.00329≤x≤0.7000) were prepared in order to investigate the mechanism of ionic motion and the interactions existing in these systems. The study was carried out by impedance spectroscopy in the 20-Hz to 1-MHz range at different temperatures. Real and imaginary components of conductivity spectra in terms of equivalent circuit analysis (EC) and correlated ionic motion analysis based on a generalized universal power law (UPL) were investigated. Results revealed that in the PEG400/(MgCl2)x, the ionic species formed in the bulk materials are crucial for the overall conductivity. Indeed, in PEG400/(MgCl2)x, conductivity is ionic and takes place through hopping of the cationic species Mg2+ and [MgCl]+ between the coordination sites present along the polyethereal chains.