CeO2-ZrO2-Sm2O3 anodes for intermediate temperature-solid oxide fuel cells

Ce0.9Zr0.1-xSmxO2-δ (0 ≤ x ≤ 0.1) mixed oxides were synthesized for the first time via the citrate-nitrate self-combustion method and, interfaced with 20 % Sm doped CeO2, were studied as metal-free anode materials for Intermediate Temperature- Solid Oxide Fuel Cells. The effect of Sm2O3 incorporation in the Ce0.9Zr0.1O2 structure on the electrocatalytic properties of the anodes under wet H2 and wet CH4 was investigated. The processes involved in the anode performance were identified analyzing the Electrochemical Impedance Spectroscopy results by combining Equivalent Circuit fitting and Distribution of Relaxation Time deconvolution methods. A new anode material with optimized composition (Ce0.9Zr0.04Sm0.06O2-δ), and extremely low polarization resistance without the need of a metallic phase was obtained (0.011 Ω.cm2 and 0.004 Ω.cm2 at 750 °C in 7 vol% H2 and 40 vol% H2, respectively; 0.14 Ω.cm2 and 0.09 Ω.cm2 at 750 °C in 7 vol% CH4. and 20 vol% CH4, respectively).