Fabrication and electrical properties of nanocrystalline Dy3+-doped CeO2 for intermediate-temperature solid oxide fuel cells

High-quality nano-sized Ce0.8Dy0.2O2−δ powders were synthesized by the solution combustion method, using C4H7NO4 (aspartic acid) as the combustion fuel. The nano-sized Ce0.8Dy0.2O2−δ powders provided an ultra-fine grain size and high density even at low sintering temperatures (1250–1400 °C), engendering high electrical conductivity. The magnitude of electrical conductivity depended strongly on the sintering temperature and followed the order of 1350 °C > 1300 °C > 1250 °C > 1400 °C. The electrical conductivity of the Ce0.8Dy0.2O2−δ sintered at 1350 °C was 0.206 S cm−1 at 800 °C. The high electrical conductivity can lower operating temperature of solid oxide fuel cells. We demonstrate that synthesizing nano-sized powders and controlling grain size are important for enhanced Ce0.8Dy0.2O2−δ electrolytes.