Yuta HANAMURA

Activity of the Lanthanium-Nickel-Iron Perovskite Oxide as the cathode for Solid Oxide Fuel Cells

Kazunori SATO

Solid oxide fuel cells (SOFCs) are a promising power generation system owing to the high energy-conversion efficiency. It is important to develop new materials for anode, electrolyte, and cathode to improve the cell performance. In this research, a new cathode material has been investigated.
La(Ni,Fe)O3 (LNF) shows a much higher electronic conductivity than the conventional cathode material (La,Sr)MnO3 (LSM). Since loading effects of the LNF cathode on the cell performance has not been investigated so far, we examined the electrode reaction of LSM compared with that of LSM.
In this research, J-V characteristic, a cathodic overvoltage measurement by the DC current interuption method, and an interfacial resistance measurement by the AC impedance method were performed to examine the performance of the LNF cathode. The LNF cathode showed lower overvoltages than the LNF cathode.
The increase in the oxygen-reduction reaction rate is appeared to be caused by the high electronic conduction of LNF.
The electrode reaction occarring at the interface between the LNF cathode and the zirconia-based electrolyte requires a high activation energy than that for the LSM cathode. This difference is most likely to be caused by the porous microstructure of the cathode.


However, LNF cathode need thermal energy more than the LSM by the charge movement reaction on electrolyte/cathode interface. If heat is given enough, LNF cathode shows an electrode reaction mechanism that is higher than the LSM. From these, LNF cathode and the difference of the electrode reaction mechanism of the LSM cathode were found.