Electrochemical performances of monolithic BaCe0.85Y0.15O3-d tri-layer as fuel cell and electrolyzer device

"Monolithic" reversible solid oxide fuel cells have been investigated by impedance spectroscopy and continuous current measurements. All the cell layers have been made of yttrium-doped barium cerate (BaCe0.85Y0.15O3-??, which shows a mixed (protonic and anionic) conductivity, and assembled in three compartments: cathode/electrolyte, central membrane (porous), anode/electrolyte. Due to the mixed conductivity of the material, both the H+ and the O2- species can migrate through the electrolyte and form H2O inside the porous central membrane (CM), avoiding the dilution of fed gas at the fuel or the oxidant chamber. The influence of operating temperature and gas partial pressures has been studied both in the solid oxide fuel cell (SOFC) and in the electrolyser (SOEC) mode. Electrochemical tests have shown the successful reversibility of the cell, as well as a satisfactory stability in the performances. If compared to intermediate-temperature or protonic ceramic fuel cells, monolithic resulted in lower performances, likely due to a not still optimised structure of the central membrane.