Tokyo Institute of Technology Department of Applied Chemistry, Graduate School of Science and Engineering 2-12-1 Ookayama Meguro-ku, Tokyo 152-8552 Japan 2-12-1 Ookayama Meguro-ku, Tokyo 152-8552 Japan
NOF corporation Alkylene Oxide Group 2, Oleochemicals Research Lab. 3-3 Chidori-cho Kawasaki-ku, Kawasaki, Kanagawa 210-0865 Japan 3-3 Chidori-cho Kawasaki-ku, Kawasaki, Kanagawa 210-0865 Japan
We have focused on the poly(ethylene glycol) (PEG)-borate ester as a new type plasticizer for solid polymer electrolyte for
lithium ion secondary battery. Adding the PEG-borate ester into the electrolyte shows the increase in the ionic conductivity
of the polymer electrolyte. By measuring the glass-transition temperature of the polymer electrolytes with DSC, it is found
that the increase in ionic conductivity of the polymer electrolyte is due to the increase in ionic mobility. By investigating
the temperature dependence of the ionic conductivity of the polymer electrolytes using William-Landel-Ferry type equation,
we considered that the PEG-borate ester does not have any influence for dissociation of Li-salt.