Electroless plated and in-situ formed CuO coating on SUS 430 stainless steel interconnect for solid oxide fuel cell

To alleviate the adverse effects of Cr induced cathode poisoning in interconnects of solid oxide fuel cells (SOFCs) and slow the surface area specific resistance (ASR) growth, applying potential protective coating layers is a promising strategy. CuO stands out due to its exceptional resistance to Cr migration and high electronic conductivity (2 × 10³ S cm⁻¹ at 700 °C). In this study, CuO coating is deposited on SUS 430 substrates using electroless plating followed by in-situ thermal oxidation, which is very suitable for preparing protective film on steel interconnect with uneven surface. The coating shows good resistance to oxidation reaction, reducing the parabolic rate constant from 4.83 × 10⁻⁷ mg² cm⁻⁴ s⁻¹ to 2.03 × 10⁻⁷ mg² cm⁻⁴ s⁻¹ after 1000 h oxidation at 800 °C. The coating also shows good resistance to Cr diffusion, restraining the formation of the chromium oxide scale under the same thermal conditions. Consequently, the coating reduces the ASR values by 51.6 % for 200 h and showing a resistance of 15.72 mΩ cm² for 1000 h heating both at 800 °C in air. In addition, the coating greatly suppresses cathode degradation in a 100-h durability symmetrical cell test at 800 °C. Therefore, this work proves the advantages of electroless plating strategy for SOFC interconnect coating and provides a good guidance for the future development.