Highly dense and chemically stable proton conducting electrolyte sintered at 1200 °C

Abstract

The BaCe 0.7 Zr 0.1 Y 0.2-x Zn x O 3- (x = 0.05, 0.10, 0.15, 0.20) has been synthesized by the conventional solid state reaction method for application in protonic solid oxide fuel cell. The phase purity and lattice parameters of the materials have been studied by the room temperature X-ray diffraction (XRD). Scanning electron microscopy (SEM) has been done for check the morphology and grain growth of the samples. The chemical and mechanical stabilities have been done using thermogravimetric analysis (TGA) in pure CO 2 environment and thermomechanical analysis (TMA) in Argon atmosphere. The XRD of the materials show the orthorhombic crystal symmetry with Pbnm space group. The SEM images of the pellets show that the samples sintered at 1200 o C are highly dense. The XRD after TGA in CO 2 and thermal expansion measurements confirm the stability. The particles of the samples are in micrometer ranges and increasing Zn content decreases the size. The conductivity measurements have been done in 5% H 2 with Ar in dry and wet atmospheres. All the materials show high proton conductivity in the intermediate temperature range (400-700 o C). The maximum proton conductivity was found to be 1.0  10-2 S cm-1 at 700 o C in wet atmosphere for x = 0.10. From our study, 10 wt % of Zn seems to be optimum at the B-site of the perovskite structure. All the properties studied here suggest it can be a promising candidate of electrolyte for IT-SOFCs.

Improved mechanical strength, proton conductivity and power density in an ‘all-protonic’ ceramic fuel cell at intermediate temperature

“…High density and high ionic conductivity are two of the most important criteria for an electrolyte for solid oxide fuel cells. A small percentage of Zn doping at the B-site 37 or adding a sintering additive 38 increases the density and performance of the electrolyte. Zn doping has advantages over Ni for better sintering, crystal structure and density.…”

Improved Mechanical Strength, Proton Conductivity and Power Density in an ‘All-protonic’ Ceramic Fuel Cell at Intermediate Temperature

“…High density and high ionic conductivity are two of the most important criteria for a good electrolyte. A small percentage of Zn doping at the B-site 37 or adding a sintering additive 38 increases the density and performance of the electrolyte. Zn doping has advantages over Ni for better sintering, crystal structure and density.…”

Evaluation of BaCo0.4Fe0.4Zr0.2−xNixO3−δ perovskite cathode using nickel as a sintering aid for IT-SOFC

“…To use a sintering aid, it is crucial that dopant can increase the point defects, and it can also enhance the transportation of ions or electrons to promote sintering. 21,22 Nickel is considered as to be fast diffuser and it enhances the sintering rate of the ceramic powders. It was also reported that during sintering the addition of nickel suppresses the coarsening process of grains to some extent.…”