Solid oxide fuel cells with proton-conducting La0.99Ca0.01NbO4 electrolyte

Several proton conductive ceramic oxides are evaluated for potential application in ceramic-NiO composite anodes for proton-conducting La0.99Ca0.01NbO4 (LNO) electrolyte-based fuel cells. Chemical compatibility tests show that most of the existing proton-conducting oxides are unfavorable for application in LNO electrolyte-based fuel cells because of undesirable reactions at high temperatures. Further considering the chemical compatibility with NiO and the ability to promote the densification of the deposited LNO electrolyte, LNO-NiO composite anode proves to be the only suitable anode candidate. With humidified hydrogen (similar to 3% H2O) as the fuel and static air as the oxidant, fuel cells based on LNO electrolyte film deposited on LNO-NiO anodes show a peak power density of 24 mW cm(-2) at 750 degrees C, this value being one of the largest ever reported for LNO-based cells. Further investigation reveals that the polarization resistance of the cell is the major contribution to the total cell resistance, limiting the overall cell performance. (C) 2017 Elsevier Ltd. All rights reserved.