Doped (Nd,Ba)FeO3 oxides as potential electrodes for symmetrically designed protonic ceramic electrochemical cells

The design of new electrode materials with high redox stability has great potential for the fabrication of solid oxide fuel and electrolysis cells having a symmetrical configuration; such a configuration is particularly promising in terms of economic and technological factors due to involving a reduced number of functional materials and technological steps. Under the framework of the present study, we developed new Nd1-xBaxFe0.9M0.1O3-delta materials (where M = Cu or Ni, x = 0.4 or 0.6), characterizing their functional properties (oxygen non-stoichiometry, thermomechanical and electrical properties) under both oxidizing and reducing conditions, as well as demonstrating the principal capability of their application as symmetrical electrodes in proton-conducting electrochemical cells. The obtained results demonstrate the desirability of a low barium content due to decreased thermal expansion coefficients and chemical strain contribution and Cu-doping due to the formation of an electrochemically active scaffold having nano-sized sediments. The Nd0.6Ba0.4Fe0.9Cu0.1O3-delta electrodes fabricated onto the BaCe0.5Zr0.3Y0.1Yb0.1O3-delta proton-conducting electrolytes exhibit polarization resistances of 1.1 and 15.1 omega cm(2) at 600 degrees C in wet air and wet hydrogen measuring atmospheres, respectively. These reported results are among the first concerning the effective operation of symmetrical electrodes in systems with proton-conducting electrolytes.