Durability and Performance of High Performance Infiltration Cathodes

The performance and durability of solid oxide fuel cell (SOFC) cathodes consisting of a porous Ce0.9Gd0.1O1.95 (CGO) infiltrated with nitrates corresponding to the nominal compositions La0.6Sr0.4Co1.05O3-δ (LSC), LaCoO3-δ (LC), and Co3O4 are discussed. At 600°C, the polarization resistance, Rp, varied as: LSC (0.062Ωcm2)

High temperature X-ray diffraction revealed a number of different phases in LSC and LC. The electrochemical performance of the LSC-infiltrated CGO cathode was found to depend on the infiltrate firing temperature and is suggested to originate from a complex interplay between the formation, percolation, and surface area of electronically conducting and catalytically active phases.

Simplified models that predict the Rp of LSC-infiltrated CGO were applied and showed that the performance is not only characterized by the nanoscale size of the infiltrate but also from a better surface exchange property. A 450h test of an LSC-infiltrated CGO cathode showed an Rp with final degradation rate of only 11mΩcm2kh-1.

An SOFC with an LSC-infiltrated CGO cathode tested for 1,500h at 700°C and 0.5Acm-2 (60% fuel, 20% air utilization) revealed no measurable degradation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.