Enhancing Activity, Charge Transport, Power Production, and Stability of Commercial Solid Oxide Fuel Cells with Yttria-Stabilized Zirconia Nanoparticles

Abstract

Interconnected networks of 10-30 nm yttria-stabilized zirconia (YSZ) nanoparticles dramatically enhance both the electrocatalytic activity and bulk charge transport of commercial lanthanum strontium manganite (LSM)-YSZ solid oxide fuel cell (SOFC) cathodes. The improvement in both electrode functions increases the maximum power density of the commercial SOFC by 90%. In comparison, modifying cathodes with lanthanum strontium cobalt ferrite (LSCF) and praseodymium barium cobaltite (PBC) nanoparticles, highly active catalysts with mixed ionic-electronic conductivity (MIEC), only enhances electrocatalytic activity. The combination of dual enhanced electrode functions with nanoYSZ results in a maximum power density that is 50% and 11% higher than LSCF and PBC, respectively. Finally, the performance stability over time is highest for nanoYSZ modified cells.

Progress in Material Development for Low-Temperature Solid Oxide Fuel Cells: A Review

“…These materials simultaneously offer both electronic and ionic conductivity with high transport properties that could result in gaining a high density of electrocatalytic active sites in their structure. In the case of MIEC cathodes, penetrating the oxygen reduction sites into the bulk of the electrodes can extend the oxygen reduction area from the TPBs to the bulk of the cathode, and hence it reduces the cathode polarization losses [50,[56][57][58]. The electronic conductivity of the MIEC composites can be increased by introducing those dopants that could generate oxygen vacancies in the bulk of the material [59].…”

“…Generally, non-stoichiometric oxides with the perovskite structure (ABO 3 ) are classified as a type of MIECs. For example, La x Sr 1−x Co y Fe 1−y O 3−δ (LSCF)-Ce x Gd 1−x O 2−δ (GDC) composite has been reported to be the state-of-the-art cathode MIEC [56]. Wu et al [61] investigated the electrochemical performance of La 1.5 A 0.5 NiO 4+δ (A = Ca, Sr or Ba) cathode materials for intermediate-and low-temperature applications.…”

Lowering the Impedance of Lanthanum Strontium Manganite-Based Electrodes with Lanthanum Oxychloride and Lanthanum Scavenging Chloride Salts

“…6 The most common approach has been to infiltrate mixed ionic-electronic conductors (MIECs), such as doped-cerias and doped-cobaltites, into the porous LSM-YSZ electrode, forming nanoparticles of MIECs on the LSM-YSZ surface. [6][7][8][9][10][11] These infiltrant modifications have been shown to lower the cathode reaction impedance and researchers ascribe the improvement to increasing both electrocatalytic activity and the effective density of active sites. [6][7][8][9][10][11] In our own work, we have recently shown that infiltrating YSZ nanoparticles into LSM-YSZ cathodes results in a lower total impedance and higher power density than infiltrating with praseodymium barium cobaltite (PBC) nanoparticles, a highly active MIEC.…”

“…[6][7][8][9][10][11] These infiltrant modifications have been shown to lower the cathode reaction impedance and researchers ascribe the improvement to increasing both electrocatalytic activity and the effective density of active sites. [6][7][8][9][10][11] In our own work, we have recently shown that infiltrating YSZ nanoparticles into LSM-YSZ cathodes results in a lower total impedance and higher power density than infiltrating with praseodymium barium cobaltite (PBC) nanoparticles, a highly active MIEC. 11 Importantly, the nano-YSZ was shown to significantly improve the impedance of both bulk charge transport (35% reduction) and the reaction processes (40% reduction), whereas PBC lowered the reaction impedance by 53% but only lowered the bulk charge transport impedance by 6%.…”

“…[6][7][8][9][10][11] In our own work, we have recently shown that infiltrating YSZ nanoparticles into LSM-YSZ cathodes results in a lower total impedance and higher power density than infiltrating with praseodymium barium cobaltite (PBC) nanoparticles, a highly active MIEC. 11 Importantly, the nano-YSZ was shown to significantly improve the impedance of both bulk charge transport (35% reduction) and the reaction processes (40% reduction), whereas PBC lowered the reaction impedance by 53% but only lowered the bulk charge transport impedance by 6%. Furthermore, the degradation rate of the nano-YSZ cell was 0.23%/100 h, more than three times lower than the PBC cell, 0.73%/100 h. Although PBC was more effective in lowering the reaction impedance, the combination of significant improvement in bulk charge transport and reaction processes with nano-YSZ resulted in a higher fuel cell power density.…”