Vacuum cold sprayed nanostructured La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ as a high-performance cathode for porous metal-supported solid oxide fuel cells operating below 600 °C

Porous metal-supported solid oxide fuel cells (PMS-SOFCs) demonstrate potential to dramatically reduce their costs while simultaneously enhancing the durability of SOFCs. However, owing to the unsatisfactory performance improvement of PMS-SOFCs at low temperatures and available fabrication processes, their commercial applications are limited. In this study, exceptional performance of PMS-SOFCs for electricity generation at low temperatures (400–600 °C) with vacuum cold sprayed (VCS) nanostructured La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF) as the high-activity cathode, the plasma-sprayed Ce_0.8Gd_0.2O_2−δ/La_0.8Sr_0.2Ga_0.8Mg_0.2O_3−δ (GDC/LSGM) bilayer as the electrolyte, and a cermet consisting of the nickel–gadolinium-doped-ceria (Ni–GDC) composite as the anode. By carefully controlling the spray particle size, a nanostructured LSCF cathode is obtained, and the oxygen reduction reaction (ORR) is activated. Consequently, the microstructurally optimized cell exhibits remarkable peak power densities of >1 W/cm² at 600 °C and >0.2 W/cm² at 450 °C. Moreover, this nanostructured cathode maintains high activity over 1000 h at 550 °C due to the stable microstructure, strontium (Sr) surface segregation, and the exceptional stability of PMS-SOFCs. Our results demonstrate a simple route to dramatically improve the performance and stability of PMS-SOFCs operating at low temperatures by using a nanoscale cathode for activity toward the ORR.