Inkjet printing infiltration of Ni-Gd:CeO₂ anodes for low temperature solid oxide fuel cells

The effect of inkjet printing infiltration of Gd_0.1Ce_0.9O_2- in NiO-Gd_0.1Ce_0.9O_2- anodes on the performance of symmetrical and button cells was investigated. The anodes were fabricated by inkjet printing of suspension and sol inks. Symmetrical cells were produced from composite suspension inks on Gd_0.1Ce_0.9O_2- electrolyte. As-prepared scaffolds were infiltrated with Gd_0.1Ce_0.9O₂ ink. Increasing the number of infiltration steps led to formation of "nano-decoration" on pre-sintered anodes. High resolution SEM analysis was employed for micro-structural characterization revealing formation of fine anode sub-structure with nanoparticle size varying in the range of 50-200 nm. EIS tests were conducted on symmetrical cells in 4% hydrogen/argon gas flow. The measurements showed substantial reduction of the activation polarization as a function of the number of infiltrations. The effect was assigned to the extension of the triple phase boundary. The i-V testing of a reference (NiO-8 mol% Y₂O₃ stabilized ZrO₂/NiO-Gd_0.1Ce_0.9O_2- /Gd_0.1Ce_0.9O_2- /Gd_0.1Ce_0.9O_2- -La_0.6Sr_0.4Co_0.2Fe_0.8O_3- ) cell and an identical cell with infiltrated anode revealed ~2.5 times improvement in the maximum output power at 600 °C which corresponded with the reduction of the polarization resistance of the symmetrical cells at the same temperature (2.8 times). This study demonstrated the potential of inkjet printing technology as an infiltration tool for cost effective commercial SOFC processing.