Conventional polymer electrolyte batteries have higher energy densities and are safer than traditional lead-acid batteries, but still have issues with solvent leaking and low transference numbers due to the mobility of both cations and anions. In single ion conducting polymers, or ionomers, the anion is covalently attached to the polymer backbone, which eliminates any anion motion and provides a cation transference number of unity. The cation is dissolved within the polymer matrix, which eliminates the need for solvent, thus eliminating the issue of solvent leaking. However, one of the main limitations with ionomer systems is their typically low conductivity at room temperature. The motion of the lithium cation through the polymer matrix was studied in a model polymer system with the intent to understand how the cation motion relates to the structure and dynamics of the polymer matrix, ultimately influencing conduction. Lithium cation motion in poly(ethylene oxide)-based sulfonate ionomers was investigated using nuclear magnetic resonance spectroscopy in samples with varying ion content and varying molecular weight of the poly(ethylene oxide) spacer. 7Li self-diffusion coefficients were determined using a pulsed-field gradient stimulated-echo pulse sequence and compared to results obtained from dielectric relaxation spectroscopy.?  ?

Investigation of lithium cation motion in PEO-based ionomers for applications in energy conversion and storage devices

246th National Meeting (2013)

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