Effect of TiO(2) as an additive on the sintering performance of Sm-doped CeO(2)-based electrolyte for solid oxide fuel cells

In this work, TiO(2) was selected as an additive to the Sm(0.2)Ce(0.8)O(2-δ) (SDC) electrolyte and its influence on the electrolyte properties were investigated. The tetrabutyl titanate hydrolysis product was introduced into the SDC samples as a source of TiO(2). The lattice contraction of SDC was observed by XRD when the smaller ionic radius Ti(4+) (0.605Å) were substituted for Ce(4+) (0.97 Å). XRD analysis shows that the doping content of the TiO(2) in SDC should be limited to 1 wt% to maintain the single-phase cubic fluorite structure of the SDC and avoid impurity phases. SEM characterizations suggest that the addition of TiO(2) significantly promoted the grain growth and the sintering activity, especially when doping with 0.5 wt% of TiO(2). The electrochemical measurements reveal that the addition of TiO(2) had little effect on the conductivity of SDC samples, which was 0.0306 S cm(−1) at 700°C. This study shows that 0.5 wt% TiO(2) doping can effectively improve the sintering activity without reducing the SDC performance.