Use of Microelectrode Arrays to Directly Measure Diffusion of Ions in Solid Electrolytes: Proof of Concept Experiments Involving Ag+ in a Solid Polymer Electrolyte
Interim technical rept. no. 30, 1 Jun 1988-1 Jun 1989
MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF CHEMISTRY
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We report proof of concept experiments demonstrating a new methodology for direct measurement of molecular or ionic species in electrolyte media. A microelectrode array of closely spaced Platinum microelectrodes allows direct measurement of the movement of Silver cations in aqueous electrolyte and in the solid polymer electrolytes, LiCF3SO3MEEP MEEP poly bis2-2- methoxyethoxy ethoxyphosphazene at 298 K with a molar ratio of LiCF3SO3 to polymer repeat unit of 1 to 4 and LiCF3SO3PEO PEO polyethylene oxide at 352 K and a molar ratio of LiCF3SO3 to polymer repeat unit of 1 to 8. The crucial experiments involve anodically stripping Ag from a Ag-coated Pt microelectrode generator and electrochemically detecting the resulting Ag at nearby Pt electrodes collectors by reducing the Ag back to Ag. The time dependence of the collector current corresponding to Ag to Ag reduction after the generation step allows evaluation of the diffusion coefficient, D, for the Ag in the various media and conditions used. Keywords Lithium methafluorosulfite.
- Physical Chemistry