Fabrication of Bi0.95-xEr0.05MxO1.5-δ (M = Lu, Ho, and Gd) electrolyte for intermediate temperature solid oxide fuel cells

• Published in: Journal of the Australian Ceramic Society 2019-09, Vol.55 (3), p.711-718
• Main Author: Ermiş, İsmail
• Format: Article
• Language: English
• Subjects: Ceramics; Chemistry and Materials Science; Composites; Glass; Inorganic Chemistry; Materials Engineering; Materials Science; Natural Materials
• ISSN: 2510-1560; 2510-1579
• DOI: 10.1007/s41779-018-0282-4

In this study, the samples of Lu 2 O 3, Gd 2 O 3 , and Ho 2 O 3 are firstly chosen as co-dopants with Er 2 O 3 in order to stabilize δ phase Bi 2 O 3 ceramics. The effects of co-dopants were investigated on phase stability and electrical conductivity of Bi 0.95-x Er 0.05 M x O 1.5-δ (M = Lu, Gd, and Ho) with x = 0.05 and 0.1 M ratio concentrations. The phase structure of samples was determined by X-ray diffraction method, the features of surface morphology are shown by scanning electron microscope, and the electrical conductivity is measured by AC impedance spectroscopy. All the samples have a face-centered cubic structure ( fcc ) at a lower sintering temperature (850 °C). The unit cell parameters are reduced due to the smaller dopant cations than Bi 3+ . The change of electrical conductivity in terms of the ionic radii, amount of doping, and temperature of the samples was investigated. The electrical conductivity increases with the radius of the doping ions. However, the increased amount of doping reduces conductivity. At the same time, the electrical conductivity of all the samples has increased with temperature. The best conductivity values are 0.489, 0.341, and 0.258 Scm −1 at 800, 700, and 600 °C, respectively for Bi 0.90 Er 0.05 Gd 0.05 O 1.5. These values are significantly higher than the values found in the literature.