Measurement of LiClOsub 4 Diffusion Coefficient in Propylene Carbonate by Moire Pattern

The binary (molecular) diffusion coefficients of in propylene carbonate (PC) solution was measured by the Moiré pattern method. The Moiré pattern method has the advantage over standard electrochemical techniques in that it allows simultaneous measurements of local, i.e., concentration-dependent, diffusivities over the concentration range used in one single experiment, whereas electrochemical methods yield a single effective (i.e., integral) diffusivity over the same concentration range. At , the variation of the binary diffusion coefficient with concentration is from at to at . Linear extrapolation to the dilute concentration region yields a diffusion coefficient of (at ), in reasonable agreement with the self-diffusion coefficient of ion in nonaqueous solutions measured by the pulsed-gradient spin echo nuclear magnetic resonance technique. The Stokes–Einstein parameter of the diffusivity is independent of concentration within 9% over the range and yields a Stokes radius for the pair of approximately .