The Effect of Co and Zn Addition on Densification and Electrical Properties of Ceria-Based Nanopowders

Abstract

In this work, cobalt and zinc-doped Ce 0.8 Gd 0.2 O 1.9 samples were prepared starting from a commercial nanopowder and compared to the undoped material. The powder samples were pressed and afterwards sintered by a two-step procedure, before characterization by X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Impedance Spectroscopy (IS) in air. Cobalt or zinc additions are effective as sintering aid, allowing peak sintering temperatures around 1000°C to reach densifications above of 93% of theoretical density, showing no evidence for the presence of secondary phases. The total conductivity at 800 °C of pressed Zn-doped samples (6.7x10 -2 S/cm) and Co-doped samples (7.5x10 -2 S/cm) is similar for undoped samples (7.2x10 -2 S/cm) showing that Zn and Co has a positive effect on densification without compromising the electrical conductivity.

Influence of the autocombustion synthesis conditions and the calcination temperature on the microstructure and electrochemical properties of BaCe0.8Zr0.1Y0.1O3−δ electrolyte material

“…Nevertheless, the composition is not the only pertinent parameter, and the link between microstructure and electrochemical properties of SOFC materials have been widely studied: tuning of the microstructure, and more precisely of the grains size, has been reported, either by changing the calcination temperature for LSCF perovskite anodes [21] and LSF cathodes [22] for instance, or by changing the pressure and temperature of sintering by spark plasma sintering for LSZO electrolyte material [23]. It has been shown that the microstructure of BCZY derivatives can be controlled by varying synthesis routes [24][25][26][27][28][29][30][31], tuning the composition including additional elements [32,33] or adding sintering aids [27,[34][35][36][37][38][39][40], with a balance between grain and grain boundary contributions which have been in some cases separated by using electrochemical impedance spectroscopy (EIS) [15,41].…”

Gadolinium doped ceria interlayers for Solid Oxide Fuel Cells cathodes: Enhanced reactivity with sintering aids (Li, Cu, Zn), and improved densification by infiltration

“…Nicholas and De Jonghe [18] compared the effect of many elements (additives) on the densification of GDC, and the highest densification values were obtained with the addition of Li, Zn, Co, and Cu. Most studies on sintering aids for doped-ceria were focused on pellets densification and characterization of their electrical conductivity [19][20][21][22][23][24][25], with the aim to build anode supported cells with doped-ceria electrolytes, but few papers addressed the influence of these sintering aids on the electrode performance when used as additives in GDC interlayers. As the Co addition in GDC has been widely studied [26][27][28], we focused our efforts on the three other candidates, i.e.…”

Recent Advances and Challenges in Thin-Film Fabrication Techniques for Low-Temperature Solid Oxide Fuel Cells

“…However, the addition of sintering additives can decrease the conductivity of the electrolyte, especially in the presence of SiO 2 impurities by increasing the grain boundary resistance [266]. For example, it was reported that cobalt oxide and copper oxide are useful additives in promoting the sinterability of ceria solid solutions (i.e., GDC); however, most of the added cobalt and copper ions were found to segregate at the grain boundaries [267,268]. When studying the microstructure and conductivity of doped ceria, background impurities, such as SiO 2 , are of major concern.…”