DC POLARIZATION OF POLYMER ELECTROLYTES

The steady-state current flowing in a polymer electrolyte when a constant potential is applied to a symmetric cell of the type M(s)\M+X-(polymer)\M(s) has been determined as a function of both the magnitude of the dc potential and the salt concentration in amorphous PEO:LiCF3SO3 and PEO:LiClO4 systems. Such measurements may be used to determine a practical electrolyte parameter, the current fraction, which is defined as the ratio of the current flowing when the cell is passing a steady state current following establishment of a stable concentration gradient, to the current flowing in the absence of a concentration gradient. In addition, the range of linear steady state current-applied potential difference response has been evaluated, which can, under certain circumstances, be interpreted in terms of the extent of ion association in the polymer electrolyte.