Authors: J-D Jeon, M-J Kim, J.W. Chung and S-Y Kwak
Affilation: Seoul National University, Korea
Pages: 581 - 584
Keywords: porous membranes, polymer electrolytes, TiO2 nanoparticles, ionic conductivity
In order to ameliorate the performance of polymer electrolytes, we report on a novel solvent-free polymer electrolyte filled with viscous poly(ethylene oxide-co-ethylene carbonate) (P(EO-EC)) into a porous membrane. In addition, to enhance the conductivity and mechanical strength of polymer electrolytes, TiO2 nanoparticles are added to both a porous membrane and an electrolyte mixture. Viscous P(EO-EC) (Mn = 1, 800 g mol-1) was successfully synthesized via ring opening polymerization using ethylene carbonate (EC), which is usually used as an organic solvent in gel polymer electrolytes. The P(EO-EC) showed perfect amorphous nature due to the random structure of ethylene oxide and ethylene carbonate groups in the repeating unit. From Energy dispersive spectrometer (EDS) analysis, it was confirmed TiO2 in porous membranes had a homogeneous distribution. The membranes with 10 wt% TiO2 showed better mechanical properties than the others and was therefore selected as an optimal matrix to prepare polymer electrolytes. All polymer electrolytes with the optimized Li-salt concentration (1.5 mmol LiCF3SO3/g-P(EO-EC)) obeyed Arrhenius behavior and showed linear enhancement of ionic conductivity with increasing the temperature. In addition, maximum conductivity of 4.7 _ 10-5 S cm-1 at 25 oC was obtained for the polymer electrolyte containing 1.5 wt% TiO2 in electrolyte mixture.