Elevated sintering capability and electrical conductivity of Fe2O3-doped Ce0.8Sm0.1Nd0.1O2-δ as an electrolyte in IT-SOFCs

Ce0.8Sm0.1Nd0.1O2-δ (SNDC) is one of the most promising electrolyte materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). However, the adverse effect on the preparation of the electrolyte due to the high sintering temperature of SNDC limits the application of SNDC as an electrolyte material in IT-SOFCs. In this work, x mol % (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5) Fe-doped SNDC (xFe-SNDC) powders were firstly fabricated by sol-gel synthesis, and then the corresponding bulks were prepared by cold-pressing and sintering at 1200∼1400 °C. The effects of Fe-doping on the sintering capability and electrical conductivity of SNDC were investigated. The results showed that Fe-doping leads to significant improvements in both the relative density and the electrical conductivity of SNDC. Doping Fe reduced the sintering temperature of SNDC from 1400 °C to 1200 °C and the relative density of 0.5Fe-SNDC sintered at 1200 °C reached 95.85%. Moreover, 0.5Fe-SNDC possessed the maximum conductivity of 0.0674 S cm−1 at 750 °C, which was attributed to the highest density and the highest conductivity of grain plus grain boundary.