Enhancing the Mechanical Strength of Electrolyte-Supported Solid Oxide Cells with Thin and Dense Doped-Ceria Interlayers

Abstract

The penetration of fuel cells and electrolyzers in energy systems calls for their scale-up to the gigawatt (GW) level. High temperature solid oxide cells (SOC) offer unrivaled efficiencies in both electrolysis and fuel cell operation. However, they are made of ceramics and are brittle by nature. Consequently, a high mechanical strength to avoid failure during stacking is essential to achieve a high manufacturing yield. Here, we show that without changing the materials of the state-of-the-art cells, thin and dense ceria interlayers enable comparable power densities and durability in fuel cell operation. The sole tuning of the morphology and processing of the interlayers reduce the residual stress in the cell significantly which increases its mechanical strength by up to 78%. These results promise performance gains of similar magnitude by enabling a substantial decrease of the electrolyte thickness while maintaining robustness. This stress engineering approach presents a way to increase the volumetric power density and material efficiency of SOC systems.

Intercalation of Thin-Film Gd-Doped Ceria Barrier Layers in Electrolyte-Supported Solid Oxide Cells: Physicochemical Aspects

“…In this phase, x could be between a few and 10 mol % and the Ce–Gd ratio would be similar to CGO20. This hypothesis is also consistent with our recent work, where we observed an even more pronounced shift of the CGO peaks to higher angles after exposing the CGO/YSZ interface to temperatures ∼1300 °C, suggesting increased interdiffusion …”

“…This hypothesis is also consistent with our recent work, where we observed an even more pronounced shift of the CGO peaks to higher angles after exposing the CGO/YSZ interface to temperatures ∼1300 °C, suggesting increased interdiffusion. 34 4.2. Electrochemical Testing of Electrolyte-Supported Cells.…”

Sulfur Impurities in COx Feed Gases of Solid Oxide Cells: Effect on Degradation and Removal Strategies

“…Since the experiment was carried out at OCV, the degradation was likely correlated with a purely catalytic phenomenon. In our previous work, cells of the same type were shown to be thermo-chemically stable in hydrogen-fueled fuel cell durability tests with the absence of Ni/CGO fuel electrode degradation (16,17). Hence, the degradation was probably due to impurities in the feed gas.…”

“…For the measurements, raster areas were set at 20 µm x 20 µm and 10 µm x 10 µm. Secondary ion mass species of 16 O -, 32 S -, 58 Ni -, and 140 Ce 16 Owere analyzed simultaneously with a multicollection system. Image processing was carried out with the WinImage ver.…”

Performance analysis of a metal-supported intermediate-temperature solid oxide electrolysis cell

“…To prevent the chemical reaction of YSZ with the anode perovskite material such as LSCF, GDC is often used as the barrier layer coated on the surface of YSZ. A thin and dense barrier layer of GDC could reduce the residual stress and increase the mechanical strength of the multi-layer electrolyte by up to 78% (Riegraf et al, 2021). For SOFC applications, GDC is also often employed as the main electrolyte that can operate at the intermediate temperature range of 550-700 °C.…”