High Performance Commercial SOFC Cathodes Achieved with YSZ Nanoparticles

The electrochemical performance of solid oxide fuel cell (SOFC) cathodes was improved via integration of ultra-high surface area ceramic nanoparticles, up to 115 m²·g^-1, generated with a novel processing method herein introduced. The processing method generates the high surface area nanoparticles at traditional SOFC sintering temperatures in two steps. In the first step, a hybrid inorganic-organic material comprising the ceramic precursors is sintered in an inert atmosphere at any temperature between 850°C-1350°C. During this step, an amorphous carbon template is generated in situ, preventing coarsening of the ceramic nanoparticles. The carbon template is then removed during the second step by a mild calcination in air at 700°C. Yttria-stabilized zirconia (YSZ), lanthanum strontium cobalt ferrite (LSCF), gadolinium-doped ceria (GDC), and strontium titanate (STO) have all been successfully prepared by this method. YSZ nanoparticles (nYSZ) were incorporated into a lanthanum strontium manganite-YSZ (LSM-YSZ) cathode of a commercial cell, resulting in a 90% increase in maximum power density. Impedance spectroscopy indicates the large improvement in power density was attributed to a combination of significant improvement in polarization resistance, a 45% decrease, and ohmic resistance, a 35% decrease. Remarkably, the performance of the cell modified with nYSZ was higher than cells modified with two mixed ionic electronic conductors (MIEC): Pr_xBa_1-xCo_3-δ (PBC) and La_xSr_1-xCo_yFe_1-yO_3-δ (LSCF). Both MIECs enhanced the density of active sites, but, unlike nYSZ, did not significantly improve ohmic resistance. The results demonstrate a novel pathway to achieve high performance in commercial SOFCs.