High temperature electrolysis cell performance characterization

Abstract

Electrochemical cells employing yttria-stabilized zirconia solid electrolyte were evaluated in the electrolysis of steam at 800–1050°C. Performance levels of 1.23 V at 300 mA cm −2 were obtained with current efficiencies approaching 100%. A limiting current was approached when hydrogen content in the steam exceeded approximately 90% (650 mA cm −2; 1000°C). Voltage-current behavior prior to diffusion control folllows a Tafeltype slope of approximately 250 mV per decade. Polarization in this region has a temperature dependence corresponding to approximately d ln 1/d(1/ T) = 30,000/R which permits prediction of cell performance above the 1050°C maximum testing temperature.