Fabrication of proton-conducting yttrium-doped barium zirconate electrolytes for solid oxide fuel cells

Abstract

Proton-conducting Solid Oxide Fuel Cells (H-SOFCs) have seen an increase in its popularity due to its relatively low operating temperatures, as compared to other types of fuel cells. Of the different materials selected as the electrolyte for the H-SOFCs, the one that has retained its popularity to date is yttrium-doped barium zirconate (BZY).

The objective of this project is to find out the optimum way of fabricating a BZY electrolyte pellet, as well as an anode pellet based on the combination of Nickel Oxide (NiO) and BZY. Various steps in fabricating the pellets were utilised, including the creation of a sol gel, calcination leading to powders, as well as sintering of powders into pellets. The goal is to achieve a lower operating temperature for the electrolyte pellet, as well as a porous anode substrate for the SOFC.

Tests were also conducted on the pellets to assess their performance as electrolytes and anodes, and hence a determination of the suitability of the fabrication methods. The test includes X-ray diffraction (XRD) tests, Scanning Electron Microscope (SEM) test, as well as conductivity test.

The results were indicative that the conductivity of a dense BZY electrolyte is sufficient for fuel cell operation at temperatures at 700oC and above, at which the conductivity is 3.15x10-3S/cm.