Tailoring Ion-Containing Polymers for Energy Storage Devices James Runt, Department of Materials Science & Eng, Penn State Univ. Development of safer and high-conductivity, polymer-based electrolytes for Li-ion batteries is a critical challenge. Single-ion-conducting poly(ethylene oxide)-based ionomers are an ideal model system for exploring the parameters affecting free ion fraction and conductivity. Overall program goal: develop an understanding of the relationship between local and large-scale ion structure and conductivity in solid polymer electrolytes so that design parameters for mechanically durable, high-conductivity SPEs can be established. Ultra-small-angle X-ray scattering patterns of fully sulfonated ionomers Initial experiments focused on PEO-based ionomers with vary cations, sulfonation fractions, and PEG spacer lengths. Both the intensity and power-law slope of the low-q upturn depend on these parameters. At higher ion contents, there is some evidence of thermal history dependence. An additional amorphous ion-containing polymer system was explored: poly(vinyl methyl ether) with varying concentrations of perchlorate salts. Results include significant evidence for a relationship between cation- polymer interactions and the low-q upturn. Synthesis of this information will (1) clarify the nature of the spatial fluctuations that give rise to this poorly understood scattering feature in amorphous polymer systems, and (2) enhance our understanding of ion structure and its relationship to conductivity in electrolyte materials. -3.7 -2.0