The Effect of Precusor Gel Desiccation, Ceria Oxide Pre-Infiltration, and Precursor Solution Additives on Infiltrated Lanthanum Strontium Ferrite-Lanthanum Strontium Cobaltite Solid Solution Nano-Particles

Abstract

Here, average La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) nano-particle sizes were controllably modulated from 48 to 24 nm by desiccating La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) precursor nitrate solutions or infiltrating La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) precursor nitrate solutions into Ce0.9Gd0.1O1.95 (GDC) scaffolds pre-infiltrated with a large amount of GDC nano-particles. Scanning electron microscopy, thermo-gravimetric analysis, and x-ray diffraction experiments conducted on decomposed/decomposing precursor gels within, and outside of, porous GDC scaffolds showed that desiccation and pre-infiltrated nano-GDC resulted in reduced nitrate decomposition temperatures and reduced La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) average particle sizes. GDC scaffolds infiltrated with La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) precursor gels, desiccated with CaCl2, and subsequently fired at 700oC, contained high-phase purity La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) nano-particles with average particle sizes ranging from 31-27 nm. GDC scaffolds pre-infiltrated with nano-GDC infiltrated particles, infiltrated with La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) precursor gels and subsequently fired at 700oC, contained high-phase purity La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) nano-particles with average particle sizes ranging from 29-24 nm. In contrast to comparable, standard nano-composite cathodes (NCC’s) containing 48 nm average-sized La0.6Sr0.4CoxFe1-xO3-δ (0≤x≤1) particles and achieving polarization resistances of 0.10 Ωcm2 at 640°C, the best CaCl2-dessicated NCC’s achieved 0.10 Ωcm2 at 600°C, while the best pre-infiltrated nano-GDC NCC’s achieved 0.10 Ωcm2 at 540°C. Acknowledgements This work was supported by National Science Foundation award number CBET-1254453. Figure 1. Scanning electron micrographs for La0.6Sr0.4CoxFe1-xO3-δ nano-particles produced inside a GDC scaffold at 700°C for citric acid-containing precursor gels that were standard (a-e) desiccated (f-j) and pre-infiltrated nano-GDC oxide particles (k-o). Note, LSF = La0.6Sr0.4FeO3-x, LSFC = La0.6Sr0.4Fe0.8Co0.2O3-x, LSCF55 = La0.6Sr0.4Fe0.5Co0.5O3-x, LSCF = La0.6Sr0.4Co0.8Fe0.2O3-x, and LSC = La0.6Sr0.4CoO3-x. All scale bars are 50 nm in width. Figure 1