Oxygen Ion-Conductivity and Chemical Stability of Ceria Based-Electrolyte in Composite with Sodium Carbonate as Electrolyte for Direct Biodiesel-Fuel Cells

In this research CeO2 was doped with samarium to produce Samarium doped-Ceria, SDC, then composited with sodium carbonate to produce NSDC. Two types of NSDC had been prepared, i.e. NSDC1 and NSDC2, correspond to different methods of incorporating sodium carbonate in which were without and with pre-heating procedures, respectively. The ionic conductivity of NSDCs at 300°C to 600°C was calculated by measuring the impedance at 20 Hz to 5 MHz. The result showed that additions of sodium carbonate for NSDC1 eliminate electronic conductivity of SDC at 600°C, however it reduces the ionic conductivity. NSDC2 did not provide a good ionic conductivity, although this electrolyte showed electronic conductivity at given temperatures. This indicates that NSDC2 is not suitable for electrolyte but more suitable for electrode material. Stability measurements on a single cell of NSDCL|NSDC|NSDCL revealed that the addition of sodium carbonate can inhibite diffusion of electrode's elements into electrolyte. This could increase fuel cell stability.