The development of Intermediate-Temperature Solid Oxide Fuel Cells (IT-SOFC) as high efficient energy conversion systems requires the optimization of its components: cathode, anode and electrolyte.  CeO₂-based materials present excellent catalytic properties for the oxidation of H₂ and CH₄ fuels. Through the incorporation of metals oxides (Gd₂O₃, Sm₂O₃, Y₂O₃) in the CeO₂ lattice the ionic conductivity can be significantly improved, becoming good electrolytes, particularly (Ce,Gd)O_2-d (CGO) compound. Furthermore, the addition of metals such as Ni or Cu enhances the material electronic conductivity, thus enabling them as efficient IT-SOFC anodes [1].

It is recognized that the polarization characteristics of Ni-CGO cermet anodes are strongly affected by their preparation conditions, which determine the microstructure and morphology of these materials. For that reason, further exploration of new microstructures has to be done in order to improve anode performance [2]. In a previous work we presented a new modified sol-gel method to incorporate Ni into the precursors solution, which produced a powder with a very homogeneous Ni distribution resulted in smaller particle sizes with narrower distribution than the commercial cermet [3]. In this work, we present a study of the performance of these anodes sintered at different temperatures for the hydrogen oxidation reaction. The electrode polarization resistance is evaluated through Electrochemical Impedance Spectroscopy (EIS) on symmetric cells, while the cell power of Ni-CGO/CGO/LSCF configuration is measured in a home-made equipment. The structural and morphological characterization are analyzed by X-Ray Diffraction and Transmission and Scanning Electron Microscopy, respectively. The study of the oxidation state and coordination of Ce and Ni in these cermets, simulating in-operando conditions, was performed using synchrotron Dispersive X-ray absorption spectroscopy (DXAS) technique. The correlation between the electrochemical behavior, electronic properties and microstructural characteristics will be discussed.

[1] W.C. Chueh, Y. Hao, W. Jung and S.M. Haile, Nature Materials 11 (2012) 155-161.

[2] Z. Liu, B. Liu, D. Ding, M.F. Liu, F.L. Chen, C. R. Xia, Journal of Power Sources 237 (2013) 243-259.

[3] A. Fernandez Zuvich, A. Soldati, S. Larrondo, M. Saleta, D.G. Lamas, L. B. Baqué, A. Caneiro and A. Serquis, ECS Transactions  64 (2014) 233-240.