Ionic Conductivity and Viscosity Behavior of PMMA-based Nano-dispersed Polymer Gel Electrolytes Containing Lithium Perchlorate

Introduction: In this study, nano-dispersed polymer gel electrolytes containing polymethylmethacrylate (PMMA), lithium perchlorate (LiClO4), diethyl carbonate (DEC), dimethylacetamide (DMA), and nano-sized fumed silica (SiO2) have been synthesized and characterized. Materials and Method: Polymer gel electrolytes were prepared by adding PMMA (Aldrich) to the liquid electrolytes of LiClO4 (Aldrich) in DEC and DMA (Merck), along with continuous stirring. Nanosized fumed silica (SiO2) (Aldrich) having particle size 7 nm with surface area 380 m2/g was added (wt% of gel electrolytes) along with continuous stirring to obtain homogeneous nano-dispersed polymer gel electrolytes. Results and Discussion: The electrolytes showed high ionic conductivity for electrolytes with higher dielectric constant solvents. The polymer enhanced the ionic conductivity of liquid electrolytes having a lower dielectric constant solvent (DEC) at all PMMA concentrations than the electrolytes containing a high dielectric constant solvent (DMA). Further, with the addition of nano-sized fumed silica, the ionic conductivity showed a small increase along with an increase in the mechanical stability of the electrolytes. The viscosity behavior of the electrolytes was also discussed, and it was correlated with the results of the ionic conductivity of electrolyte. Nanodispersed polymer gel electrolytes exhibited high ionic conductivity (10-2 S/cm). Conclusion: Further, the conductivity showed only a small change (by a factor, not by an order) over the 25-100°C temperature range and did not vary with time, which is desirable for their use in practical applications.