A lanthanum and calcium co-doped A-site deficient strontium titanate (LSCT A-) was used as alternative anode material in Solid Oxide Fuel Cells (SOFC) with an active area of 100 cm 2 . Cell performance was tested in both short (5 cell) stack configuration, as well as a full HEXIS Galileo system (nominally 1 kW AC). Impregnation with various electrocatalysts, such as nickel and ceria, yielded promising fuel cell performance at this scale. The system test initially produced 70% of the nominal output power and is to the authors' knowledge the first all-oxide SOFC test on this scale. The strontium titanate backbone provides sufficient electronic conductivity to ensure acceptable ohmic losses. Power densities up to 200 mA cm -2 could be obtained at 900°C, which compares well with Ni-cermet based anodes. Degradation is however severe at 900°C, due to impregnate coarsening, but operation at 850°C minimizes this effect. Short stacks could be stably operated for 1600 hours with an output power of 100 mA cm -2 . Stacks are redox stable, but currently not sulphur tolerant.

and useful electrical power from a fuel gas (e.g., natural gas), at much higher conversion efficiencies than conventional combustion methods. [1,2] This method of heat and electricity co-generation makes SOFC technology ideal for use in micro-combined heat and power (µ-CHP) units, particularly in the 1-5 kW (electrical power) output class, which may be used to satisfy the total heat and electricity demand of family homes and small businesses. An example of such a unit is the Galileo 1000 N, produced by HEXIS AG between 2013 and 2018. [3] This µ-CHP unit was successfully commercialized with more than 100 units being installed in a variety of locations across Western Europe, each providing 1 kW of electrical power and 20 kW of heat (from an auxiliary burner). [4,5] Currently, the Swiss SOFC manufacturer is focusing on the development of the next-generation SOFC-based µ-CHP unit, designed to provide an increased electrical power output of 1.5 kW at a higher electrical efficiency. [3,6] Typically, high-temperature SOFC (operating at 700-850 °C) are produced using traditional, well-studied, and effective material sets, which have been tailored to suit the requirements of each component. For example, air electrodes (cathodes) are often made from composites of yttria-stabilized zirconia (YSZ) and strontium-substituted lanthanum manganite (LSM) [7][8][9] or composites of cerium gadolinium oxide (CGO) and strontium-substituted lanthanum cobaltite (LSC), [9,10] ferrite (LSF), [11] or cobaltite ferrite (LSCF). [8,[12][13][14][15][16] Electrolytes used in SOFC operating within this temperature regime are zirconia stabilized, commonly, with scandia or yttria (ScSZ or YSZ), [2] while fuel electrodes (anodes) traditionally comprise composites of Ni and either YSZ or CGO. [2,17] However, despite the excellent performance that can be obtained using these materials, there are several challenges posed, specifically, by the anode materials, that must be addressed in order to provide greater resistance to harsh operating conditions in next-generation SOFC systems. These ceramic-metal composites (cermets) of YSZ/CGO and Ni exhibit redox instability, due to the propensity of Ni to agglomerate, in addition to sulfur poisoning and carbon deposition during exposure to unprocessed natural gas feeds. [1,18] Several different materials design approaches have been identified and explored in an attempt to mitigate the limitations of the Solid oxide fuel cell (SOFC) stack technology offers a reliable, efficient, and clean method of sustainable heat and electricity co-generation that can be integrated into micro-combined heat and power (µ-CHP) units for use in residential and small commercial environments. Recent years have seen the successful market introduction of several SOFC-based systems, however, manufacturers still face some challenges in improving the durability and tolerance of traditional Ni-based ceramic-metal (cermet) composite anodes to harsh operating conditions, such as redox and thermal cycling, overload exposure, sulfur poisonin...

Hexis is developing the micro-CHP SOFC-system Galileo 1000 N. Field tests with the Galileo 1000 N were started and at present 17 systems are installed in the field. Additional 13 systems are installed at Hexis' labs. In a system test with improved cells, an electrical power output of more than 1000 W (AC, net), an electrical efficiency of more than 40% (DC) and 36% (AC, net) could be achieved, while another test showed a total efficiency of more than 90% (LHV). One of the lab systems runs now for more than 15000 h with a power degradation rate of 1.9% per 1000 h. A 5-cell stack with a similar setup is running for more than 15000 h with a voltage degradation of approx. 1% / 1000 h, while a more recent test showed less than 0.5% / 1000 h degradation for 9000 h. In the field, a system has been operated for more than 7200 h until now. It was shown that 5-cell stacks can tolerate more than 12 full redox-cycles.

Hexis is the developer and manufacturer of the SOFC-based Micro-CHP system Galileo 1000 N. More than 60 Galileo 1000 N systems have been installed up to now and are in operation at customer's sites and in the lab. In the lab, long-term system operation of more than 28000 hours has been achieved. With beginning of 2010 a cell with increased performance has been established as a new standard. An AC net electrical efficiency of the system (including all peripheral consumptions) of 30 to 35 % has been achieved and the overall (electrical + thermal) efficiency of the system is in the range of 90 to 105 % (LHV). On stack level, cells with even higher performance were tested, resulting in electrical efficiencies of up to 44 % (DC) with CPOx reforming and 57 % (DC) with steam reforming.

Solid oxide fuel cells (SOFC) comprising LSM-YSZ/LSM composite cathodes, 6ScSZ electrolytes and La0.20Sr0.25Ca0.45TiO3 (LSCTA−) anode ‘backbone’ microstructures were prepared using thick-film ceramic processing techniques. Activation and decoration of the LSCTA−...