Conductivity and transference number measurements on polymer electrolytes

Straightforward methods based on dc techniques are described which permit reliable evaluation of both the total conductivity and transference numbers of binary polymer electrolytes. In theory, under restricted conditions, transference numbers may be obtained from polarisation data on cells of the type M(s) ƒM+X−(polymer)ƒM(s). In practice such measurements are frequently complicated by electrode resistances. Here methods are demonstrated for reliably extracting transference numbers in the presence of such effects; measurements are presented for PEOLiCF3SO3 (9:1) electrolyte as a function of temperature. Use of a simple four-electrode cell for the measurement of polymer electrolyte conductivity by dc methods is also described and results are given for the same electrolyte.