An Estimation of the Electrode‐Electrolyte Contact Area by Linear Sweep Voltammetry in Pt / ZrO2 Oxygen Electrodes

Abstract

The contact area between the platinum paste electrode and the zirconia electrolyte was estimated on the basis of a linear relationship between the peak area of linear sweep voltammetry and the actual contact area. The latter area was measured by microscopic observation of the contact area from one side of a transparent zirconia single‐crystal disk on the other side of which the platinum paste had been sintered. Applying the peak area vs. contact area relationship obtained to the same platinum electrode sintered on polycrystalline zirconia disks, the contact area was estimated from the voltammogram peak. The electrode performance increased monotonically with increasing contact area, but there was a small deviation from the proportional relationship. This deviation was corrected by using the length of the three‐phase boundary, instead of the contact area, as a morphological parameter.