Next Generation Electrically Conductive and Protective Coating for Planar SOFC Stacks

Ferritic stainless steels are preferred to interconnect materials for intermediate temperature SOFCs because of their resistance to oxidation, high formability, and low cost. However, their protective oxide layer produces Cr-containing volatile species at SOFC operating temperatures and conditions, which can cause cathode poisoning. Electrically conducting spinel coatings have been developed to prevent cathode poisoning and to maintain an electrically conductive pathway through SOFC stacks. PNNL demonstrated the Mn-Co-O type of spinel coating on the interconnect part and delivered a great result. However, the industrial partners need the cost down of these coating materials. Hence, PNNL starts investigating next-generation coating materials. This paper will focus on the electrically conductive coating process.