Random Copolymerization\nof Substituted Dioxolanes:\nRational Design of High-Performance Polymer Electrolytes

Polymer electrolytes enhance the safety of lithium-ion\nbattery\nsystems, but current state-of-the-art poly(ethylene oxide)-based polymer\nelectrolytes fail to achieve the electrochemical properties necessary\nfor practical applications. We probed the impact of substituent density\non the electrolyte performance by introducing methyl substituents\ninto the backbone of a series of poly(1,3-dioxolane) (PDXL)-based\ncopolymers. The polymerization of 1,3-dioxolane (DXL) and 4-methyl-1,3-dioxolane\n(MeDXL) yielded a series of random copolymers that were amorphous\nabove 10% MeDXL incorporation. The copolymers with 10 and 20% MeDXL\nincorporation exhibited higher efficacies than those of either PDXL\nor poly(ethylene oxide) (PEO), highlighting the use of methyl substituents\nto control the electrochemical properties of polymer electrolytes.