Study on Structural and Electrical Properties of Ce0.5Zr0.5O2 for Applications in SOFC Anodes

The redox properties of dense pellets of Ce0.50Zr0.50O2 have been investigated by temperature programmed reduction (TPR) (1023-1373K) and mild temperature oxidation (873K) cycles, X-ray powder diffraction technique (XRD), RAMAN spectroscopy and electrochemical impedance spectroscopy (EIS) have been used to characterize structural and conductivity modifications. The redox treatments promote both the reducibility at lower temperature and the electrical conductivity of this material. A gradual transition from a tetragonal to a pyrochlore cubic phase with the progress of reduction has been observed, while the nature of the phase after reoxidation depends on the temperature of reduction. The promotion of conductivity is correlated with the partial reordering of cationic lattice, but not specifically with the formation of the kappa-phase.