Synthesis and characterization of nanostructured Cux (Mn1.5-x/2Co1.5-x/2)O4 as an interconnect coating for solid oxide fuel cell

Document Type : Research Paper


1 Renewable Energy Department, Niroo Research Institute (NRI), Tehran, Iran

2 Renewable Energy Department, Niroo Research Institute, Tehran, Iran


Manganese-Cobalt Oxide (MCO) spinel oxide is a promising composition as a protective coating for the metallic interconnects of a SOFC. In an effort to reach better properties, such as suitable thermal expansion match, good electrical conductivity, and fine structural stability, various elements have been doped in the spinel structure. In this study, the effect of Cu addition as a dopant on the electrical properties of MCO spinel is investigated. Powders with a nominal composition Cux(Mn1.5-x/2Co1.5-x/2)O4 (x=0, 0.15, and 0.3) were successfully synthesized based on the sol-gel Pechini method. The phase composition and microstructure of the synthesized powder were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The XRD results revealed that a pure phase with a spinel structure was obtained for different amounts of doped samples. The microstructural characteristics of the synthesized powders revealed that the average particle size of the powder decreased from about 84nm to 52nm with the introduction of Cu. To evaluate the effect of Cu on the sintering behavior of MCO, the powder was pressed and sintered at 1200°C for 2h. The density measurement and FESEM results showed that the addition of Cu promotes the sintering mechanism, and the density was improved. In addition, the electrical properties of the samples were evaluated using the 2probe direct current technique at different temperatures. The results revealed that the addition of 0.3 Cu increased the electrical conductivity of the sample from 0.102 to 0.218 at 800°C. This significant improvement can be attributed to the promotion of sintering and also facilitating electron flow by substitution of Cu+2 cations in the spinel structure.


Main Subjects

1.              Ghorbani-Moghadam, T., et al., Characterization, Electrical and Electrochemical Study of La0.9Sr1.1Co1−xMoxO4 (x ≤ 0.1) as Cathode for Solid Oxide Fuel Cells. Journal of Electronic Materials, 2020. 49(11): p. 6448-6454.
2.              Mohebbi, H., et al., The Effect of Process Parameters on the Apparent Defects of Tape-Cast SOFC Half-Cell. Advanced Ceramics Progress, 2019. 5(4): p. 12-16.
3.              Salari, F., et al., Hybrid additive manufacturing of the modified electrolyte‐electrode surface of planar solid oxide fuel cells. International Journal of Applied Ceramic Technology, 2020. 17: p. 1554
4.              Yoon, K.J., et al., Advanced ceramic interconnect material for solid oxide fuel cells: Electrical and thermal properties of calcium- and nickel-doped yttrium chromites. Journal of Power Sources, 2010. 195(22): p. 7587-7593.
5.              Zeng, Z., et al., A review of heat transfer and thermal management methods for temperature gradient reduction in solid oxide fuel cell (SOFC) stacks. Applied Energy, 2020. 280: p. 115899.
6.              Hassan, M.A., O.B. Mamat, and M. Mehdi, Review: Influence of alloy addition and spinel coatings on Cr-based metallic interconnects of solid oxide fuel cells. International Journal of Hydrogen Energy, 2020. 45(46): p. 25191-25209.
7.              Talic, B., et al., Diffusion couple study of the interaction between Cr2O3 and MnCo2O4 doped with Fe and Cu. Solid State Ionics, 2019. 332: p. 16-24.
8.              Pandiyan, S., A. El-Kharouf, and R. Steinberger-Wilckens, Formulation of spinel based inkjet inks for protective layer coatings in SOFC interconnects. Journal of Colloid and Interface Science, 2020. 579: p. 82-95.
9.              S, S.K., et al., Solution precursor plasma spray process: A promising route for the fabrication of Mn-Co oxide based protective coating for SOFC. Surface and Coatings Technology, 2017. 324: p. 26-35.
10.           Cheng, F. and J. Sun, Fabrication of a double-layered Co-Mn-O spinel coating on stainless steel via the double glow plasma alloying process and preoxidation treatment as SOFC interconnect. International Journal of Hydrogen Energy, 2019. 44(33): p. 18415-18424.
11.           Park, B.-K., et al., Cu- and Ni-doped Mn1.5Co1.5O4 spinel coatings on metallic interconnects for solid oxide fuel cells. International Journal of Hydrogen Energy, 2013. 38(27): p. 12043-12050.
12.           Hong, J.-E., et al., Properties of Spinel Protective Coatings Prepared Using Wet Powder Spraying for SOFC Interconnects. ECS Transactions, 2015. 68: p. 1581-1587.
13.           Akanda, S. and M.E. Walter. Investigation of Manganese Cobalt Oxide (MCO) Coatings on Fuel Cell Interconnects. in Experimental and Applied Mechanics, Volume 6. 2011. New York, NY: Springer New York.
14.           Yang, Z., et al., Thermal Growth and Performance of Manganese Cobalite Spinel Protection Layers on Ferritic Stainless Steel SOFC Interconnects. Journal of The Electrochemical Society - J ELECTROCHEM SOC, 2005. 152.
15.           Miguel-Pérez, V., et al., The effect of doping (Mn,B)3O4 materials as protective layers in different metallic interconnects for Solid Oxide Fuel Cells. Journal of Power Sources, 2013. 243: p. 419-430.
16.           Xu, Y., et al., Cu doped Mn–Co spinel protective coating on ferritic stainless steels for SOFC interconnect applications. Solid State Ionics, 2011. 192(1): p. 561-564.
17.           Ma, S.-Z., et al., Effect of microstructure, grain size, and rare earth doping on the electrorheological performance of nanosized particle materials. Journal of Materials Chemistry, 2003. 13(12): p. 3096-3102.
18.           Duan, X., W. Luo, and W. Wu, New theory for improving performance of electrorheological fluids by additives. Journal of Physics D: Applied Physics, 2000. 33(23): p. 3102-3106.
19.           Molin, S., et al., Co-deposition of CuO and Mn1.5Co1.5O4 powders on Crofer22APU by electrophoretic method: Structural, compositional modifications and corrosion properties. Materials Letters, 2018. 218: p. 329-333.
20.           Masi, A., et al., The effect of chemical composition on high temperature behaviour of Fe and Cu doped Mn-Co spinels. Ceramics International, 2017. 43(2): p. 2829-2835.
21.           Szymczewska, D., et al., Microstructure and Electrical Properties of Fe,Cu Substituted (Co,Mn)3O4 Thin Films. Crystals, 2017. 7(7): p. 185.
22.           Brylewski, T., et al., Structure and electrical properties of Cu-doped Mn-Co-O spinel prepared via soft chemistry and its application in intermediate-temperature solid oxide fuel cell interconnects. Journal of Power Sources, 2016. 333: p. 145-155.
23.           C J, D.K., et al., Transition Metal Doping of Manganese Cobalt Spinel Oxides for Coating SOFC Interconnects. Journal of The Electrochemical Society, 2014. 161: p. F47.
24.           Lee, K., et al., Evaluation of Ag-doped (MnCo)3O4 spinel as a solid oxide fuel cell metallic interconnect coating material. International Journal of Hydrogen Energy, 2017. 42(49): p. 29511-29517.
25.           Fernández-Ropero, A.J., et al., High valence transition metal doped strontium ferrites for electrode materials in symmetrical SOFCs. Journal of Power Sources, 2014. 249: p. 405-413.