Effect of additive salts on ion conductivity characteristics in solid polymer electrolytes

Effects of lattice energy of the additive salt on ionic species and ion conductivity characteristics were studied in the solid polymer electrolyte. Poly[oligo(oxyethylene) methacrylate] and several lithium salts were used as matrix and additive salt for solid polymer electrolytes, respectively. Salt and salt content deeply affected the ion conductivity characteristics as well as morphology even for amorphous type solid polymer electrolytes. The relationship between ion conductivity at constant reduced temperature (T - T_g = 90°C) and lattice energy of the additive salt was evaluated at each salt content. A different relationship was found for each salt content. Multiple ion aggregate formation was considerably affected by the salt, and was revealed to be effective to increase the ion conductivity.