Strategy to improve phase compatibility between proton conductive BaZr_0.8Y_0.2O_3−δ and nickel oxide

Abstract

BaZr 0.8 Y 0.2 O 3Àd (BZY20) is a promising candidate as an electrolyte in protonic ceramic fuel cells (PCFCs), and nickel (Ni) is known to show good electrode properties for the anode reaction. However, their compatibility seems to be questionable, since during the co-sintering process for cell fabrication, a second phase of BaY 2 NiO 5 formed due to a reaction between BZY20 and NiO. The results in this work revealed that BaY 2 NiO 5 was unstable against high temperature (1500 and 1600 C), and could also be reduced in a hydrogen atmosphere at 600 C. The products of these reactions may affect fuel cell performance. A systematic work was then performed to provide fundamental insight into the reactivity between BZY20 and NiO, which was found to be impacted significantly by the compositional homogeneity of the BZY20 powder used for cell fabrication, and also the BaO activity during the cosintering process. It is concluded that improving the compositional homogeneity of BZY20, by elevating the final heating temperature for BZY20 from 1300 to 1600 C in this work, and choosing a proper sintering strategy may improve effectively the phase purity of the cell.

Correlation between Concentrations of Ni and Y in Y-Doped BaZrO3 Electrolyte in Co-Sintered Cells: A Case of Controlled NiO Activity by Using MgO-NiO Solid Solution as Anode Substrate

“…BaZrO 3 and BaZr 1− x Y x O 3−δ ( x = 0.02, 0.05, 0.1, 0.12, 0.15, 0.17, 0.2, 0.22) samples were synthesized with the solid-state reaction method. The detailed process was reported in our previous works [17,18]. For convenience, the BaZr 1− x Y x O 3−δ samples were named as BZY100 x .…”

Correlation between Phase Behavior and Electrical Conductivity of 10 mol % Y-Doped BaZrO3: An Anomalous Dispersion Effect-Aided Synchrotron Radiation XRD Study Combined with TEM Observation and Electrochemical Analysis

“…In addition, some starting materials, including BaCO3, ZrO2, and Y2O3, also remained in such assynthesized sample. 25,26 When the sample was sintered at 1600 o C for 8 h, as shown in the insets of Figure 7, all the reflections exhibit the feature of two peaks, indicating the co-existence of two cubic perovskite phases, rather than lattice distortion from the cubic perovskite crystal structure. With the sintering time extending to 24 h and longer, the diffraction peak at the low angle side turns to be sharper, implying improvement in crystallinity.…”

Manipulating the grain boundary properties of BaCeO3-based ceramic materials through sintering additives introduction

“…Nickel oxide (NiO) is often used as such an additive. However, no improvement (or even deterioration) of grain boundary transport is observed [16][17][18][19][20]; this is due to two undesirable effects: very low solubility of Ni 2+ -ions in a Ce-sublattice of BaCeO 3 -based materials and, consequently, the sedimentation of proton-blocking Ni-containing phases (NiO, BaY 2 NiO 5 ) along the grain boundaries. Therefore, a rational search of possible alternative to NiO is a matter of fundamental and applied interests associated, respectively, with design of PCOs with optimized properties and their successful application in EDs.…”