Abstract
•Ce1−xLaxO2−δ (x = 0 − 0.1) solid solutions showed linear increase in ionic conductivity with La3+•Ea is 1.49, 0.94, 0.87 and 0.70 eV for x = 0, 0.01, 0.03, 0.05 and 0.1 composition.•LDC showed highest ionic conductivity of 1.01 × 10−2 S cm−1 at 750 °C.•Electronic and ionic transference numbers are 0.20 and 0.80 at 700 °C for x = 0.1.•0.05 LDC showed the OCV of 0.81 V and max. power density of 41 mWcm−2.
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La-doped CeO2 nanoparticles of composition Ce1−xLaxO2−δ (0 ≤ x ≤ 0.1) have been studied here as prospective electrolytes for intermediate temperature solid oxide fuel cells (IT-SOFCs). They were synthesized by auto-combustion method and the powder samples were calcined at 700 °C to get ultrafine nanocrystalline particles. They were characterized by XRD, Raman, FTIR, XPS, DRS, FESEM/EDX, particle size analyzer and ac-impedance techniques. Ionic conductivity was measured from 350 − 750 °C. The Ce0.90La0.1O2−δ (0.1 LDC) and Ce0.95La0.05O2−δ (0.05 LDC) showed a maximum conductivity of 8.89 × 10−3 and 8.32 × 10−3 S cm−1 at 700 °C, respectively. The σt of 0.1 LDC = 1.01 × 10−2 S cm−1 at 750 °C. The activation energy of 0.1 LDC and 0.05 LDC was found to be 0.70 eV and 0.87 eV, respectively. These values are higher than those reported for La-doped CeO2 in literature. The SOFC performance with 0.05 LDC as electrolyte showed open circuit voltage of 0.81 V and maximum power density of 41 mW cm−2 at 650 °C using hydrogen as fuel.