(444e) Methacrylate Based Ionically Conductive Polymer Electrolyte for Solid State Lithium Iron Phosphate Batteries

Lithium Iron Phosphate (LFP) is a promising electrode material for energy storage that is widely viewed as a thermally resistant alternative to current state of the art lithium-ion cathode materials employed in modern electrification efforts. Solid state LFP batteries offer desirable safety, lacking from many alternatives, as it nullifies the use of flammable organic electrolytes. To date, solid-state electrolytes developed for LFP cells have been lacking in room temperature ionic conductivity, largely due to high interfacial impedance and reactivity of the solid electrolyte with electrode surfaces. However, methyl methacrylates (MMA) are the nascent trend in the realm of solid electrolyte membranes because of their low cost, malleability and reported stability with lithium metal interfaces. Through the integration of lithium salt and fillers into the conductive framework of an MMA polymer, a flexible UV curable gel polymer electrolyte was formed with promising ionic conductivity characterized through electrochemical impedance spectroscopy (EIS). The crystallinity and morphology of the formed electrolyte was investigated via X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) respectively. Electrochemical performance of the electrolyte was demonstrated in a system comprising of an LFP electrode paired with a lithium metal anode that offers a stable, room temperature, cycling capacity of 80 mAh/g. This study will provide a better understanding of the interaction of lithium salt and fillers with MMA electrolytes on the energy density and cycling stability in solid state lithium-ion batteries.