Evidence of low temperature relaxation and hopping in ion conducting polymer blend

We report sub-ambient dielectric relaxation and ion migration phenomena in a blend type solid polymer electrolyte based on PEO-PDMS-LiPF6. X-ray diffraction and scanning electron microscopy results indicate a possibility of blending between the two polymer components. It also confirmed the complexation between polymer blend and salt. Dielectric behavior of the blend electrolytes exhibits a dispersive response with clear evidence of α-relaxation at ambient and sub-ambient (30 °C to − 30 °C) temperatures. This has further been corroborated by clear relaxation peak in the modulus spectra that changes its position from lower to higher side on the frequency scale with rise in temperature irrespective of salt concentration. It is also noted that the electrolytes having higher salt concentration (Ö/Li ~ 10) exhibit long range ion migration in the low frequency limits (≤ 105 Hz) followed by short range ion migration in high frequency range (≥ 105 Hz). The latter occurs via hopping of charge carriers under thermal activation. Evidence of temperature dependent relaxation time distribution has also been noted. The dynamics of charge transport is dependent on salt concentration. Higher the salt concentration, faster is the transport process.