Double layer-type electrodes for reversible solid oxide fuel cells

We have developed double layer-type (catalyst layer/current collecting layer) electrodes for reversible SOFCs operating at medium-temperatures. As the H₂ catalyst layer (anode for SOFC and cathode for steam electrolysis) interfaced with YSZ solid electrolyte, mixed conducting samaria-doped ceria (CeO₂)_{0 8}(SmO_{1 5})_{0 2} particles were employed in combination with Ni metal electrocatalysts (10 to 20 vol.% of nanometer-size Ni) highly dispersed on their surfaces. The current collecting porous layer of Ni-SDC cermet (60 vol.% of micrometer-size Ni) was formed on the catalyst layer. The H₂-electrode with 10 vol.% Ni in the catalyst layer exhibited high performance due to the effective enhancement of the reaction rate by increasing both the active reaction sites and the electronic conductance.