Utilization of carbon dioxide for polymer electrolytes [II]: Synthesis of alternating copolymers with glycidyl ethers as novel ion-conductive polymers

Abstract For creation of a novel candidate for the polymer electrolytes without ethylene oxide units in the main chain, we considered polycarbonates obtained from the copolymerization of CO 2 with epoxy monomers. In this study, we synthesized six types of polycarbonates possessing glycidyl ethers (phenyl, tert -butyl, n -butyl, ethyl and isopropyl) and ethyl side groups using zinc glutarate, and measured the ionic conductivity of their electrolytes including LiTFSI. The electrolyte possessing ethyl glycidyl side groups had the highest conductivity and the value was 2.9 × 10 −7  S/cm at room temperature. DSC measurement showed that some of polycarbonates possessing glycidyl ethers decrease in T g by the addition of salt, whereas the polycarbonate (P(EP-C)) possessing non-ether side group increase in the T g . FT-IR measurement revealed that the P(EP-C) electrolyte clearly makes interaction between Li ions and carbonyl groups on the main chain, which is related to the main factor of the increase in T g .