INSITU MEASUREMENTS OF CONDUCTIVITY AND ACTIVE SURFACE-AREA OF POROUS-ELECTRODES BY THE CURRENT STEP METHOD .2. EXPERIMENTS

The electrical conductivity of a laboratory lead dioxide electrode immersed in a solution of H//2SO//4 was measured by the four-point dc method using a current step. Analysis of the potential drop as function of the time yielded information about conductivity of the solid phase, double layer capacity related to the internal active surface area, and transport hindrance in the pores. The conductivity decreases by less than an order of magnitude during discharge, hence it does not seem to be the limiting factor of the discharge capacity.