Structural and ionic conductivity of Cu-doped titania (Ti0.95Cu0.05O2?δ) for high temperature energy devices

The Cu-doped titania (Ti_0.95Cu_0.05O_2-δ) is studied here as a solid-state ionic conductor for its possible application in high temperature energy devices such as an electrolyte for SOFC. The sample in the powder form was obtained by solid state method using TiO₂ and copper acetate by heating up to 1200 °C for 10 h. It was characterized by XRD, FT-IR, Raman, SEM/EDS, DRS-UV-Visible, photoluminescence, BET and ac-impedance techniques. The oxide ion conductivity (σ_t) values obtained from ac-impedance measurements showed a linear increase with temperature from 300 ? 700 °C. The σ_t values are similar to that of Ln-doped ceria, and the highest conductivity of 1.41 × 10^?4 Scm^?1 was recorded at 700°C. The activation energy for total conductivity was found to be 0.82 eV. The ionic and electronic transport numbers are 0.79 and 0.21, respectively. This study suggests the plausible use of rutile TiO₂ based (low-cost and structurally stable) materials as electrolytes in SOFC.