Advance fuel cells using Al2O3-nNaAlO2 composite as ion-conducting membrane

In present work, we reported an novel oxide-salt Al2O3NaAlO2 composite, which was prepared by mixing Al2O3 and Na2CO3 two phase materials in different weight ratio, and then sintering at 1100 °C. The X-ray diffraction pattern, scanning-electron microscope and impedance spectra are applied to characterize the crystal structure, morphology and electrical properties of the Al2O3NaAlO2 composite. The Al2O3NaAlO2 composite as electrolyte membrane was sandwiched by two pieces of Ni0.8Co0.15Al0.05Li-oxide (NCAL) electrode layer to construct advanced fuel cell. Optimizing the weight ratio of Al2O3 and NaAlO2, such cell delivered an highest power density of 789 mW/cm2 and an open circuit voltage (Voc) of 1.13 V at 575 °C. The superior performance is mainly due to the excellent ion-conducting of Al2O3NaAlO2 composites and the outstanding catalysis activity of the NCAL eletrodes. The EIS results revealed that the Al2O3NaAlO2 composite possessed superior ionic conductivity of 0.121 S/cm at 575 °C. The interfacial effects between oxide-salt two phase including space-charge and structural misfit at the interface region dominated the ion transport for Al2O3NaAlO2 composite.