A Model for Diffusion and Ionic Conduction in Polymer Electrolytes

The Use of Radiotracer Diffusion to Investigate Ionic Transport in Polymer Electrolytes: Examples, Effects, and Their Evaluation

“…Depending on the radiotracer employed, activity counting can be done by γ -or β-detectors of conventional type, taking into account corrections for background radiation. Two typical diffusion profiles resulting from simultaneous diffusion of 22 Na and 125 I in PEO 500 NaI are shown in Fig. 3.…”

“…A major criterion is the half-life time (τ 1/2 ) which should preferably be longer than several days. For the alkali metal cations, the situation is favourable owing to the principal availability of 22 Na (τ 1/2 = 2.6 a), 42 K (12 h), 86 Rb (19 d), and 137 Cs (30.2 a) [12]. In addition, the nobel metal 110m Ag (τ 1/2 = 250 d) and the divalent isotopes 65 Zn (244 d) and 109 Cd (453 d) may be useful for ionic systems while 64 Cu (13 h) forms a borderline case de- manding enhanced experimental skills.…”

“…For PFG-NMR, the stable natural isotopes 7 Li and 19 F have been frequently used in the field of polymer ionics [18,19]. In the case of RTD, 22 Na and 125 I are useful radiotracers to investigate the diffusion behaviour of the corresponding ionic species. However, it proves to be difficult to find ionic systems that can be examined sufficiently well by both methods.…”

“…3. Radiotracer depth profiles of 22 Na and 125 I in PEO 500 NaI resulting from simultaneous diffusion at 120…”

“…40 μm thick) with the same composition as the sample, but doped with a tiny amount of a solution containing the radiotracer. We frequently used 22 Na and 125 I in the form of aqueous 22 NaCl and Na 125 I solutions, respectively. The source film was dried before use to remove residual water and organic solvent.…”