The Ceres Cell
Ceres has developed a unique adaptation of Solid Oxide Fuel Cell (SOFC) technology, able to operate at temperatures substantially lower than conventional designs which typically run at 800 - 1000 degrees C. By using a new generation of ceramic materials known as CGO (cerium gadolinium oxide) instead of the industry standard YSZ (yttria stabilised zirconia), operation at 500 - 600 degrees becomes possible.
This in turn allows use of conventional stainless steel as the cell substrate, separating the functions of mechanical support and electrochemistry. The electrochemical layers can be made extremely thin and optimised for maximum performance, resulting in excellent power density levels, whilst the stack material costs are radically reduced. The efficiency of converting fuel into electricity and heat is therefore very high and this efficiency is maintained across a wide part-load range. In addition, the heat-to-power ratio is approximately one-to-one making the technology ideal for applications such as CHP, where levels of electrical output need to be maintained even where heat demand is modest.
In contrast to totally ceramic cells, these metal-supported cells are mechanically highly robust and can be easily sealed (e.g. through welding) and have thermal expansion coefficients well matched to their ceramic coatings. This allows great resistance to thermal shock, permitting rapid start-up times and the potential for many on/off cycles for everyday usability. In addition, the technology retains the fuel flexibility of SOFC, and has proven ability to run highly efficiently on commercially available fuels such as natural gas, LPG and biofuels.