Synthesis and Fundamental Properties of Carbon Dioxide/Alkylene Oxide Copolymers as Ion-Conductive Polymers

• Published in: KOBUNSHI RONBUNSHU Vol. 70; no. 1; pp. 23 - 28
• Main Authors: NANTHANA, Vannasa, TOMINAGA, Yoichi
• Format: Journal Article
• Language: English; Japanese
• Published: The Society of Polymer Science, Japan 01.01.2013
• Subjects: Carbon Dioxide; Ceramics; CO2/Epoxide Copolymer; Copolymers; Electrolytes; Glass Transition Temperature; Ionic Conductivity; Liquids; Lithium-Ion Battery; Oxides; Polycarbonate; Polycarbonates; Solid Polymer Electrolyte
• ISSN: 0386-2186; 1881-5685; 1881-5685
• DOI: 10.1295/koron.70.23

Solid polymer electrolytes (SPEs) have been proposed as solid-state alternatives to liquid electrolytes in electrochemical applications such as all-polymer Li batteries. However, these suffer from low ionic conductivity in the solid state compared with common liquid, gel and ceramic electrolytes. In this study, the preparation of SPEs using an alternative copolymer obtained from CO2 with an epoxide monomer instead of polyether was proposed synthesized and evaluated as a novel polymer candidate for SPEs. We used four types of polycarbonates (PCs) possessing different alkyl side groups; the SPE samples were prepared by the addition of 20–80 mol% LiTFSI. In all PC-based electrolytes, the glass transition temperature linearly decreased and the ionic conductivity increased with increasing LiTFSI concentration. Furthermore, longer alkyl side chains in PC decreased the conductivity, because the alkyl groups prevented LiTFSI dissociation.