An easily sintered and chemically stable La2-xMgxCe2O7-δ proton conductor for high-performance solid oxide fuel cells

Abstract Mg-doped La 2 Ce 2 O 7-δ (LCO) is investigated to develop an easily sintered and chemically stable proton conductor for fabricating high-performance solid oxide fuel cells (SOFCs). All La 2-x Mg x Ce 2 O 7-δ ceramics possess a pure fluorite-type structure. The sintering activity of Mg-doped LCO increases obviously, and fully dense La 1.85 Mg 0.15 Ce 2 O 7-δ (LMCO) electrolyte membrane is successfully prepared by co-firing at the temperature as low as 1300 °C for 5 h. Besides, LMCO exhibits the highest electrical conductivity of 7.41 × 10 −3  S cm −1 in dry air and 1.55 × 10 −2  S cm −1 in wet H 2 (∼3% H 2 O) at 700 °C among the investigated oxides, and retains excellent chemical stability against CO 2 and H 2 O. The LMCO-based fuel cell also displays very encouraging power performance, reaching as high as 897 mWcm −2 at 700 °C. The results demonstrate LMCO is a promising alternative as proton conductor for achieving both chemically stable and high-performance SOFCs with reduced sintering temperature.