The Rheology of Stabilised Lanthanum Strontium Cobaltite Ferrite Nanopowders in Organic Medium Applicable as Screen Printed SOFC Cathode Layers

Abstract

The production and optimisation of screen printing (SP) pastes containing La0.58Sr0.42Co0.21Fe0.79O3 – δ and La0.61Sr0.41Co0.19Fe0.79O3 – δ (LSCF) were investigated. The application of these nanopowders is supposed to improve the cathode's microstructure and increase its mechanical strength. Thirty seven pastes containing LSCF were carried out with variation in binders, dispersants and different particle size distribution. The rheological behaviour of these pastes was investigated. It was found that commercially available dispersant Solsperse 3000 resulted in the best suspension stability, achieving almost 55 times lower viscosity value for pastes containing 20 vol.‐%, than pastes without any dispersants. The shear thinning behaviour was found to be favourable for the LSCF cathode deposition. A cathode made from the mixture of nano and submicron powder exhibits a polarisation resistance as low as 0.76 Ω cm2 at 592 °C.

Flame Spray Synthesis of Nanoscale La0.6Sr0.4Co0.2Fe0.8O3–δ and Ba0.5Sr0.5Co0.8Fe0.2O3–δ as Cathode Materials for Intermediate Temperature Solid Oxide Fuel Cells

“…This corresponds to particle diameters of about 100 to 20 nm, an optimal range for the later processing as a screen printing paste. A recently published work is dealing with the non-trivial processing and stabilisation of such nanopowder as screen printing pastes [33]. Independent from production rates up to 400 g h In general, a pronounced conductivity maximum in combination within a more narrow temperature range is observed.…”

“…Figure 10) and decomposition of this particular composition, which appears at relatively low temperatures of about 1,200°C [9,29,43], but also to the carbonate formation. One should note that the implementation of such a particle morphology in screen printing pastes, as it is the later goal for these materials, may cause difficulties in terms of paste viscosity, stabilisation or relaxation behaviour [33]. The determined cell parameters in the as-prepared condition directly after synthesis are Table 1.…”

“…4 [9,[29][30][31][32] are synthesised by a continuous, single-step FSS process from aqueous nitrate solutions at application-relevant, high production rates. It is noteworthy that the nanoparticle size was strictly limited to a specific surface area (SSA) <50 m 2 g -1 , due to the later application in screen printing pastes [33]. The reader should know that paste stabilisation and long-term stability is still a critical parameter at such a particle scale.…”

Charge compensation and magnetic properties in Sr and Cu doped La-Fe perovskites

“…together with chemical and thermal stability. Doped lanthanum ferrites are widely studied for use in catalysis [1][2][3][4], as cathode materials for solid oxide fuel cells (SOFCs) [5][6][7][8] and in chemical sensors applications [9][10]. Dann et al [11] studied the La 1-x Sr x FeO 3-w system using neutron powder diffraction measurements and Mössbauer spectroscopy.…”

Characterization and Stack Testing of Solid Oxide Fuel Cells with Cathodes Prepared by Infiltration

“…1,6,12,16 Finally, the possibility of synthesizing the electrode active phase in situ within the electrolyte pores from relatively cheap nitrate precursors may offer significant materials cost advantages over traditional electrodes, where expensive perovskite powders with finely tuned particle size distributions are required for screen-printing. 17 The results on infiltrated electrodes reported in the literature have so far been obtained almost exclusively on button cells with electrode active areas on the order of 1 cm 2 or less. A notable exception is the work by C. S. Ni et al, who have recently fabricated and tested 5 × 5 cm 2 cells where both the anode and the cathode was prepared by infiltration.…”