Innovative electrolytes based on chitosan and thulium for solid state applications: Synthesis, structural, and thermal characterization

Innovative chitosan-based polymer electrolytes, plasticized with glycerol and doped with thulium triflate (Tm(CF3SO3)3) were prepared by solvent casting technique and their properties were evaluated. The samples are thermally stable up to about 130 °C and the degradation process occurs in three stages in the case of samples containing salt. The DSC curves have shown that the addition of salt produces no significant changes in the thermograms, and the SEM micrographs indicated that the addition of salt does not promote changes of the sample surface. AFM analysis revealed that the samples' roughness increases when higher glycerol amount is added. The sample doped with 20.56% of thulium triflate exhibits ionic conductivity of 10−7 S cm−1 at 30 °C and 10−6-10− 5 S cm−1 at 90 °C. For the same sample but with high glycerol amount the ionic conductivity increases to 10−5 S cm−1 at 30 °C and 10−4 S cm−1 at 90 °C. Due to the highest conductivity values, this sample was chosen to assemble electrochromic device (ECD) and the obtained results confirm that it is promising material to be applied in ECDs.