Characteristics of Cu and Mo-doped Ca3Co4O9−δ cathode materials for use in solid oxide fuel cells. Issue 9 (July 2016)

• Record Type: Journal Article
• Authors: Wang, Sea-Fue; Hsu, Yung-Fu; Chang, Jing-Han; Cheng, Soofin; Lu, Hsi-Chuan
• Is Part Of: Ceramics international. Volume 42:Issue 9(2016)
• Page Start: 11239
• Page End: 11247
• Publication Date: 2016-07
• Subjects: Solid oxide fuel cell -- Cathode -- Impedance -- Cell performance; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2016.04.037
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: In this study, Cu and Mo ions were doped in Ca3 Co4 O9− δ to improve the electrical conductivity and electrochemical behavior of Ca3 Co4 O9− δ ceramic and the performance of a solid oxide fuel cell (SOFC) single cell based on NiO-SDC/SDC/doped Ca3 Co4 O9− δ -SDC were examined. Cu substitution in the monoclinic Ca3 Co4 O9− δ ceramic effectively enhanced the densification, slightly increased the grain size, and triggered the formation of some Ca3 Co2 O6 ; however, no second phase was found in porous Mo-doped Ca3 Co4 O9− δ ceramics even when the sintering temperature reached 1050 °C. Substitution of Cu ions caused slight increase in the Co 3+ and Co 4+ contents and decrease in the Co 2+ content; however, doping with Mo ions showed the opposite trend. Doping the Ca3 Co4 O9− δ ceramic with a small amount of Cu or Mo increased its electrical conductivity. The maximum electrical conductivity measured was 218.8 S cm −1 for the Ca3 Co3.9 Cu0.1 O9− δ ceramic at 800 °C. The Ca3 Co3.9 Cu0.1 O9− δ ceramic with a coefficient of thermal expansion coefficient of 12.1×10 −6 K −1 was chosen as the cathode to build SOFC single cells consisting of a 20 μm SDC electrolyte layer. Without optimizing the microstructure of the cathode or hermetically sealing the cell against the gas, a power density of 0.367 Wcm −2 at 750 °C was achieved, demonstrating that Cu-doped Ca3 Co4 O9− δ can be used as a potential cathode material for IT-SOFCs.