Enhanced ASC Performance at 600{degree sign}C by Ceria Barrier Layer Optimisation

Abstract

Reduction of the SOFC operating temperature to 600°C is an effective approach for reducing the costs of applied materials and increasing the lifetime of SOFC systems. The anode-supported cell design (ASC) with thin electrolyte is a promising configuration for operation at this temperature. This paper deals with the ASC performance improvement at 600 o C by optimisation of the ceria barrier layer that is placed between the La 0.6 Sr 0.4 CoO 3-δ cathode and the zirconia electrolyte to prevent the formation of resistive secondary phases. Conventional screen printing has been used for the deposition of the ceria barrier layer. The improved screen printed ceria layer results in an increase in maximum power output of the anode supprted cell from 260 to 580 mW/cm 2 at an operating temperature of 600 o C. The performance improvement was mainly caused by a significant reduction of ohmic losses.

Enhanced Performance of Gadolinia-Doped Ceria Diffusion Barrier Layers Fabricated by Pulsed Laser Deposition for Large-Area Solid Oxide Fuel Cells

“…In addition, strong limitations of wet techniques to deposit homogeneous thin layers considerably limit the potential reduction of the contribution of the barrier layer to the overall resistance by reducing the thickness. Although some works like Van Berkel et al have presented screen-printed ceria barrier layers as thin as 1.4 μm, the interdiffusion barrier layers fabricated by traditional wet deposition techniques generally present a thickness range of 2–10 μm . In addition, the porosity of these screen-printed and sequentially sintered barrier layers may be in the range 20–30%, even after sintering around 1300 °C .…”

Cr-tolerance of the IT-SOFC La(Ni,Fe)03 material

“…Probably this second drop in the conductivity reflected the moisture accelerated change of the surface of the ITM-14 foam from (Mn,Cr) 2 O 4 to pure Cr 2 O 3 scale, which results in higher concentration of volatile Cr-species [19,20,22,56], similarly to the recorded observations after 300 h exposure in air [64] (Chapter 3 of Chapter 4. Impact of Cr-poisoning on the conductivity of different LaNi 0.6 Fe 0.4 O 3 cathode microstructures this thesis).…”

“…One of the possible explanations of the nonlinear Cr-incorporation behavior might be a change in the evaporation behavior of the porous ITM-14 foam-like structure with time, in contrast to a steady Cr evaporation rate reported for the ITM-14 sheet [19,21,49]. To explain this possible change in the Cr evaporation behavior, post-test analysis was performed on the exposed ITM-14 porous foams [56]. SEM-EDX analysis revealed that the outer oxide scale formed during the exposure in dry air at 800…”

“…Such a change in the composition of the outer oxide scale of the porous ITM-14 foam will in consequence account for a different Cr release rate with time [20,56] causing the observed sudden decrease in the electronic conductivity after 300 h (Fig. 3.4) together with the corresponding increased amount of deposited Cr (Table 3.1 and Fig.…”

Optimized magnetron sputtering process for the deposition of gadolinia doped ceria layers with controlled structural properties

“…GDC layers are classically prepared by ceramic techniques such as screen printing [5] or wetchemical techniques such as spin coating [6]. However, the deposition of thin and dense layers is difficult with these techniques with typical thicknesses of a few micrometers [7].…”