(410e) Crystallinity, Thermal Properties, and Ion Transport in Salt-Containing Polymer Electrolyte Blends

Poly(ethylene oxide), PEO, has been studied extensively as a solid polymer electrolyte (SPE) for rechargeable lithium batteries as an alternative to liquid electrolytes, but performs poorly at low temperatures due to its semicrystalline nature. In an attempt to reduce crystallinity, we have blended PEO with an amorphous, conductive, polymer, poly(oligo ethylene oxide methacrylate) (POEM). A library of POEM polymers were synthesized with varying ethylene oxide side chain lengths for use in miscible blends with and without LiTFSI salts. Differential scanning calorimetry (DSC) experiments were used to investigate the miscibility and semi-crystalline properties of the blends. Ionic conductivity was measured as a function of salt concentration, blend composition, and temperature using electrical impedance spectroscopy (EIS). We aim to create a matrix of data that allows for exploration of the relationship between polymer structure, salt concentrations, and the physical, thermal, and electrochemical properties of these blends in order to understand how the presence of EO-containing side chains decrease PEO crystallinity and increase conductivity.