Liquid plasma-sprayed nanonetwork La_0.4Sr_0.6Co_0.2Fe_0.8O₃/Ce_0.8Gd_0.2O₂ composite cathodes for intermediate-temperature solid oxide fuel cells

Here, we investigated the feasibility of using a liquid plasma spray process as a novel method for the cost-effective fabrication of a nanonetwork of La_0.4Sr_0.6Co_0.2Fe_0.8O₃ (LSCF) and Ce_0.8Gd_0.2O₂ (GDC) composite as a high-performance cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). A suspension containing well-dispersed nanosized GDC particles in an LSCF precursor solution was designed as the feedstock. Particularly, the effects of GDC concentration in the suspension on the phase composition, microstructure, and electrochemical performance of the resulting composite cathode were studied. The GDC content in the final cathode increased with GDC concentration. When the GDC concentration increased to 15 g L^-1, the nanosized GDC particles distributed uniformly and continuously on the LSCF backbone to form a porous and network structure. The electrochemical studies further indicate that the cathode polarization decreased with the increase in GDC concentration from 0 g L^-1 to 15 g L^-1, whereas a further increase in the GDC concentration increased the cathode polarization instead because of the increased size of GDC clusters and decreased number of active sites. At 750 °C, the cathode prepared using the suspension with a GDC concentration of 15 g L^-1 exhibited an impressive area-specific polarization resistance of 0.009 Ω cm².