Mg2+-ion conducting poly(ethylene glycol)-TiO2 composite polymer electrolytes for solid-state batteries

Composite polymer electrolytes based on poly(ethylene glycol) (PEG), magnesium acetate [Mg(CH3COO)(2)], and x wt.% of titanium dioxide (TiO2) ceramic fillers (where x = 0, 5, 10, 15 and 20, respectively) have been prepared using solution casting technique. The X-ray diffraction patterns of PEG-Mg(CH3COO)(2) with TiO2 ceramic filler indicated the decrease in the degree of crystallinity with increasing concentration of the filler. The DSC measurements of PEG-Mg(CH3COO)(2)-TiO2 composite polymer electrolyte system showed that the melting temperature is shifted towards the lower temperature with increase of the filler concentration. Complex impedance analysis shows the existence of bulk and material-electrode interface properties of the composites. The conductivity results indicate that the maximum ionic conductivity 5x10(-5) S/cm was obtained for PEG-Mg(CH3COO)(2)-TiO2 (85-15-10) system at room temperature (303 K). The conductance spectra show two distinct regions: a dc plateau and a dispersive region. The relative dielectric constant (epsilon(r)) decreases with increase in frequency in the low frequency region whereas frequency independent behavior is observed in the high frequency region.