Application of the residue number system to the matrix multiplication problem

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Microstructural Analysis of a metal-supported SOFC after redox-cycling

A metal-supported SOFC (MSC) has been developed with the aim of an application in an auxiliary power unit (APU) for mobile systems. This cell design is expected to be more robust towards thermo-, mechanical- and chemical stresses that arise during operation of the SOFC-system when compared to the state-of-the-art anode supported cells (ASC). One of the most important cell-degradation pathways is the (partial) oxidation of the anode, due to oxygen diffusion into the fuel side of the stack during system shutdown. The oxidation of the nickel catalyst leads to an expansion of the anode and strain is induced within the cell, which results in microstructural degradation if a critical degree of oxidation is exceeded. We exposed MSC-halfcells to cyclic oxidation conditions by introducing air to the fuel side electrode followed by subsequent reduction in Ar/H2(4%). A detailed microstructural analysis of these samples is presented. Due to the novel MSC-concept, a higher critical degree of oxidation of nickel is tolerated before irreversible damage and cell failure are observed

Microstructure optimization of nickel/gadolinium-doped ceria anodes as key to significantly increasing power density of metal-supported solid oxide fuel cells

Metal-supported solid oxide fuel cells (MSCs) are promising candidates for mobile power generators like range extenders for battery electric vehicles due to their improved thermal conductivity and ruggedness. The limited space available in such vehicles heightens the need to achieve high power densities. In the present study, a significant increase in cell performance of the MSC concept of Plansee SE was demonstrated by means of systematic microstructure optimization of the complete cell architecture based on improved processing. Thickness and roughness of multi-layered Ni/GDC anode play a particularly important role in improving cell performance. After several optimization steps, a notable increase of current density from 1.29 A/cm2 to 1.79 A/cm2 at 700 °C and 0.7 V (+38%) was achieved. Additionally, lowering the anode roughness enables clear reduction of electrolyte thickness down to 2 μm, a starting point for the further enhancement of cell performance

Advances beyond traditional SOFC cell designs

Research and development of Solid Oxide Fuel Cell (SOFC) technology has been carried out at the Jülich research center for more than 20 years. A standard cell design based on a porous nickel cermet has been established and tested with stationary conditions, for which a power density of 1.25 W/cm2 at 800°C in H2 was obtained. In order to broaden the field of possible applications, new cell designs have been developed. Among those are metal-supported SOFCs (MSC), which promise increased robustness against thermal-, mechanical and chemical stresses, as well as cheaper production costs. While the MSC development may find an application in mobile devices another cell design concept aims at much lower operating temperatures. For this cell type a very thin zirconia membrane is deposited on top of a standard anode support via a multi-step sol/gel-route. With this setup a reduction of the operating temperature to 600°C with a power output of 1.25 W/cm2 could be demonstrated