The Role of Pore-Formers on Grain Interior and Grain Boundary Conductivity in Tape-Cast Porous Sheets for Electrochemical Flue Gas Purification

Ce_0.9Gd_0.1O_1.95 (CGO) electrolytes for electrochemical flue gas purification were fabricated by means of tape casting with different types, shapes and sizes of pore-formers. The sintered bodies were characterized with electrochemical impedance spectroscopy, to investigate the role of the different pore-formers on the electrochemical properties of the cast tapes. A strong effect of the different pore-formers on the conductivity (both grain interior and grain boundary conductivities) was observed. In addition, the conductivity data were also correlated with previously obtained gas permeability data. The conductivity data correlated with the permeability data in the sense that a higher permeability lead to a lower conductivity. The porosity of the samples also influenced the conductivities. The higher the porosity of the sintered bodies, the lower the conductivity was, as expected.