An ultra-fine samaria-doped ceria (Ce0.8Sm0.2O1.9, SDC) electrolyte prepared by a non-ion selective EDTA-citric complexing method is developed herein for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The rigid agglomerates due to organic compounds that exist in the SDC precursors during the EDTA-citrate complexing synthesis process inhibit crystalline growth and grain growth, leading to the generation of ultra-fine grain following the sintering procedure. Calcination is necessary above 500 degrees C for all precursors. The average grain size of the pellets after sintering at 1400 degrees C for 2 h is submicron in scale (from 200 nm to 600 nm) with various pH values, and the pellets are smaller than those obtained from other synthesis processes. Dense pellets with pH values of 10 (relative density of 99%) are obtained with precursor powder calcination at 900 degrees C for 3 h. Electrical conductivity is dependent on the calcination temperature and pH value of the solution, and the maximum electrical conductivity is 0.01 S cm(-1) at 700 degrees C with a pH value of 10. (C) 2010 Elsevier B.V. All rights reserved.