Effects of embossing structure on the performance of intermediate-temperature solid oxide fuel cells with gadolinium-doped ceria electrolyte

Using the powder-ball generation phenomenon in the electrostatic slurry spray deposition (ESSD), the embossing structures are introduced on the gadolinium-doped ceria (GDC) electrolyte to expand the cathode–electrolyte interface and three phase boundary. To verify the influence of embossing structure, the half and single cells composed of the GDC electrolyte and La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode are fabricated by the ESSD. The half cell with embossing deposited for 30 s (8.6% of electrolyte surface coverage) shows the lowest cathode polarization resistance, which is lower than that of the half cell without embossing by 62.3%. For the single cells, the maximum power densities are estimated to 0.171 W cm−2 and 1.06 W cm−2 for the cell without embossing and 0.232 W cm−2 and 1.19 W cm−2 for the cell with embossing at 550 °C and 750 °C, respectively. Additionally, the open circuit voltage (OCV) is increased by 2–5% at 550–750 °C range. According to the half and single cell results, it may be concluded that the maximum power densities and OCVs of the single cells with embossing increase simultaneously and this improvement is more effective in lower temperature range.

► The powder-balls generation phenomenon by ESSD is first reported.
► The embossing structure utilizing powder-ball is fabricated on GDC electrolyte layer.
► The cathode polarization resistance in half cell is reduced by 62.3% at 600 °C.
► The maximum power density is increased 12.41% and 35.67% at 750 and 550 °C, respectively.
► The performance enhancement by embossing structure is found to be especially suitable to IT-SOFCs.