A symmetrical solid oxide fuel cell (SOFC) with a novel microstructure of BaZr0.9Y0.1O3-delta (BZY) as the electrolyte is investigated in this study. The cell with the Ni0.8Co0.15Al0.05LiO2 (NCAL)-foam Ni/BZY/foam Ni-NCAL structure is prepared by a co-pressing method. The maximum obtained power density is 735.6 mW cm(-2) in H-2 at 550 degrees C, which is comparable to the results obtained using Ni cermet anode-supported SOFCs with an extremely thin electrolyte. The ionic conductivity of the BZY electrolyte prepared in this study is much higher than that of the conventional BZY electrolyte. The activation energy of ionic conduction is much lower than that of traditional oxygen ion or proton conduction. Electrochemical impedance spectra (EIS) results of the cell with the BZY electrolyte measured in different atmospheric conditions and the results of oxygen ion filtration experiments for the cell using the BZY/Ce0.9Gd0.1O2 (GDC) bilayer electrolyte indicate that oxygen ion is one of the carriers in the BZY electrolyte prepared in this study. According to the results of X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR), an interfacial O2- conduction mechanism at the interface of BZY particles in the electrolyte is discussed. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.