Abstract
We studied ion transport in an amorphous mixture of poly(ethylene oxide) (PEO) and sodium iodide with an O-to-Na ratio of 30. Diffusion coefficients were obtained from 22Na and 125I radiotracer experiments in the temperature range from 67 to 180 deg C. The results are compared with the dc electrical conductivity originating from frequency-dependent impedance measurements. The observed disparity between the sum of the tracer diffusivities and the charge diffusivity can be accurately described in a model that accounts for the formation of neutral pairs due to association of cations and anions.