Preparation and characterization of Ce 0.8Sm 0.2O 1.9(SDC)–carbonates composite electrolyte via molten salt infiltration

Abstract

Ce 0.8Sm 0.2O 1.9 (SDC)–carbonates composite electrolytes for SOFCs have been prepared for the first time via molten salt infiltration approach by infiltrating LiNaCO 3 molten carbonates into porous SDC ceramic. A range of techniques including XRD, SEM, Mercury Porosimeter and A.C. impedance, have been employed to characterize SDC and composite electrolytes. It has been found that the porous SDC shows a monomodal pore size distribution with average pore size of 300 nm. SDC–carbonates composite electrolytes via molten salt infiltration show a kind of SDC/carbonates co-continuous composite structure, with one SDC ceramic skeleton of bonded grains surrounded by carbonates phase. Both phases provide a continuous pathway for ionic transport and a large interfacial surface area. SDC–carbonates composite electrolytes prepared by molten salt infiltration have a higher mechanical strength than that of mixing–pressing composite electrolytes. Moreover, they show higher conductivity and lower activation energy than that of mixing–pressing composite electrolytes according to the measurements of AC impedance in the temperature range of 350 °C–650 °C.