Electrochemical characterization on SDC/Na ₂CO ₃ nanocomposite electrolyte for low temperature solid oxide fuel cells

Our previous work has demonstrated that novel core-shell SDC/Na ₂CO ₃ nanocomposite electrolyte possesses great potential for the development of low temperature (300-600 °C) solid oxide fuel cells. This work further characterizes the nanocomposite SDC/Na ₂CO ₃ electrochemical properties and conduction mechanism. The microstructure of the nanocomposite sintered at different temperatures was analyzed through scanning electron microscope (SEM) and X-ray diffraction (XRD). The electrical and electrochemical properties were studied. Significant conductivity enhancement was observed in the H ₂ atmosphere compared with that of air atmosphere. The ratiocination of proton conduction rather than electronic conduction has been proposed consequently based on the observation of fuel cell performance. The fuel cell performance with peak power density of 375 mW cm ^-2 at 550 °C has been achieved. A.C. impedance for the fuel cell under open circuit voltage (OCV) conditions illustrates the electrode polarization process is predominant in rate determination.