Evaluation of Hydrogen Ions Flowing through Protonic Ceramic Fuel Cell Using Ytterbium-Doped Barium Zirconate as Electrolyte

Abstract

To measure the proton current in a PCFC (protonic ceramic fuel cell), the proton current detector was developed using a proton conducting oxide. The amount of proton current that flowed in the PCFC can be measured by an apparatus developed based on the electromotive force of an electrochemical cell using 10 mol% In-doped CaZrO3 (hydrogen sensor) and Y-stabilized zirconia (oxygen sensor). The water vapor pressure on the cathode changed when hydrogen ions pass through the PCFC. The hydrogen ion current can be determined by monitoring the water vapor pressure. The electronic leakage was then estimated from the hydrogen ion current and external current. We measured the current of hydrogen flowing through protonic ceramic fuel cell using ytterbium-doped barium zirconate as the electrolyte. Hydrogen ions and holes were found to leak under the OCV at 700°C. The electronic leakage was found to be suppressed with the increasing electrolyte film thickness. On the other hand, no leakage of hydrogen and holes was observed at 500°C.