Study on rare earth electrolyte of SDC

The grain boundaries of polycrystalline oxygen ion conductors presented a blocking effect on the oxygen ionic transport across them. It was found that the apparent specific grain boundary conductivity was 2-3 orders of magnitude lower than the bulk conductivity in the temperature range of 200-500 degrees C for normal purity Ce0.85Sm0.15O1.925 (SDC) with an average grain size of 320-580 nm. The apparent specific grain boundary conductivity increased with decreasing average grain size. It was found that the space charge potential was nearly independent of grain size, and the reason was analyzed. The increase of the conduction path width was responsible for the increase in the apparent specific grain boundary conductivity.