Nano-structure design of doped ceria solid electrolytes for intermediate temperature operation of solid oxide fuel cell

Abstract

A review. Doped ceria (CeO2) compounds are fluorite related oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atm. As a consequence of this, considerable interest has been shown in application of these materials for 'intermediate temperature (300- 500°C)' operation of solid oxide fuel cells (SOFCs). In this review paper, our exptl. data was re-introduced to propose a new design paradigm for development of high quality doped CeO2 electrolytes. Based on our exptl. data, our original idea a control of nano-inhomogeity of doped CeO2 electrolytes was proposed. In our work, the nano-sized powders and dense sintered bodies of M doped CeO2 (M: Sm, Gd, Y, Yb, Dy, Ho, Tb and La) specimens were fabricated using ammonium carbonate co-precipitation method, conventional sintering method and pulsed elec. current sintering method. Also nano-structural features of those specimens were carefully observed for conclusion of relationship between electrolytic properties and microstructure in doped CeO2. It is essential that the electrolytic properties of doped CeO2 reflect in changes of microstructure even down to the at. scale. Accordingly, a combined approach of ultimate anal., simulation and processing route design is required to develop the superior quality doped CeO2 electrolytes for the intermediate temperature operation of SOFCs.