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.

Solid oxide electrolyzers have the potential to play an important role in a hydrogen economy in which energy, for mobile applications and electrical grid load balancing, is stored as hydrogen. The advantages of solid oxide electrolyzers for hydrogen production are 1/ the high operating temperature resulting in high electrical efficiency, 2/ the possibility to use hydrocarbon fuels as counter-feed to further increase the electrical efficiency, and 3/ the flexibility to alternately operate in fuel cell mode. This paper focuses on the use of state-of-the-art SOFC materials for air-assisted and hydrocarbon-assisted hydrogen production. Electrolyte supported cells, with 90 µm thick 3YSZ electrolyte and Ni-GDC electrode, showed comparable ASR-values in electrolyzer and fuel cell mode between 650 and 920{degree sign}C, and exhibited stable hydrogen output during a 100 hours period in both electrolyzer modes at 850{degree sign}C and 70% steam utilization. Anode supported cells, with 5µm thick 8YSZ electrolyte and Ni- YSZ electrode, showed lower ASR-values than electrolyte supported cells, which would make this cell type the most promising. However, in this case the hydrogen production was limited at steam utilizations of 50%, which seems related to mass transport limitations in the anode substrate.

SOFC anodes that contain substantial amounts of nickel, easily lose mechanical integrity due to redox cycling. One of the solutions to that, is to replace nickel with compounds that exhibit low volume changes between oxidising and reducing conditions. This paper gives the results obtained on anode assemblies with functional layer consisting of gadolinia doped ceria mixed with highly dispersed nickel and anode contact layer consisting of Ni and the perovskite La0.9Mn0.8Ni0.2O3 – δ. The results indicate that electrical conduction of this perovskite under SOFC anode conditions allows for anode assemblies with reduced nickel content, which results in increased redox resistance while high electrochemical performance is maintained. The redox tolerance that was investigated at 850 °C on electrolyte supported cells, is highest for anode functional layer consisting of 80 wt.‐% Gd0.1Ce0.9O1.95 20 wt.‐% highly dispersed nickel combined with anode contact layer consisting of 70 wt.‐% nickel and 30 wt.‐% La0.9Mn0.8Ni0.2O3 – δ, with a degradation of the current density at 0.7 V of 10% after 50 redox cycles, and 23% after 100 redox cycles. The driving force for the observed degradation is nickel agglomeration that occurs even when the nickel content is below the nickel percolation threshold.

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