The Interface Kinetics of La2NiO4+δ-Coated La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode

Infiltration technique was widely used in SOFCs electrode to enhance the cell performance. However, the oxygen transport in the cathode, especially between the extra interfaces, was still not well understood. The oxygen surface and interface exchange kinetics of La₂NiO_4+δ(LNO)-coated La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ (LSCF) have been detected by electrical conductivity relaxation method. The dense LNO layer was coated on LSCF surface to simulate the infiltrated cathode. The electrical conductivity relaxation behaviors of LNO-coated LSCF were measured at high temperature under different oxygen partial pressure from 0.2-0.02 atm. The ECR data showed that both the oxygen surface and interface exchange coefficient increased with oxygen partial pressure. The reaction rate constants for surface oxygen reduction and interface oxygen transfer were investigated based on the oxygen exchange coefficient data under different conditions, which were the fundamental knowledge for the infiltrated cathode surface and interface reaction mechanism.