Ceres Power is continuing to make excellent progress in the development of its low-temperature metal supported SOFC design (the 'Steel Cell') based predominantly around the use of ceria. This unique design architecture allows for a robust, low cost, subsidy free fuel cell product, whilst retaining the advantages of fuel flexibility, high efficiency and low degradation. Over the last year, extensive development and verification of the technology has been undertaken on the latest generation of Steel Cell technology, which offers further enhancements in technology readiness level and manufacturability. Over the same period, third parties have deepened their testing and development engagements with Ceres Power for a broadening range of market applications at cell, stack, fuel cell module and product levels. This paper provides an update on Ceres' development, verification approach and latest results.

Ceres Power's SteelCell low-temperature metal-supported SOFC technology has historically been developed to meet the requirements of 1kW e -scale micro-CHP applications. The maturity and outstanding performance demonstrated for that application means Ceres is now deploying SteelCell technology in higher power systems with partners for stationary power and automotive applications. Multiple development streams are being pursued to achieve the objectives of high efficiency (60%) and long life needed for prime power applications. This paper will discuss the progress being made to demonstrate the improvements to the fuel cell design to enhance efficiency, life, volumetric power density and fuel utilization consistent with the requirements of larger power generation units, including the development of integrated compact 5kW e stacks, power degradation rates of <0.2%/kh, DC stack efficiency of >65% and complete internal steam reforming of methane without an external reformer.

Ceres Power has developed a unique low temperature (500-620°C), low-cost metal-supported SOFC technology based on the use of thick-film Cerium Gadolinium Oxide (CGO) as the predominant oxygen ion conductor and structural ceramic, the fundamental details of which have been published previously (1). Since that paper was published, considerable progress has been made on developing the performance of the technology towards true commercial viability, particularly robustness to real-world REDOX and thermal cycling conditions, electrical efficiency and steady-state durability. These improvements have been achieved whilst maintaining the advantages of a low-temperature metal-supported design, particularly low material and balance-of-plant cost and inherent mechanical robustness. This has been demonstrated at both short-stack and 1 kW-class stack level. This paper provides a general overview of the status of Ceres SOFC technology and its applications.

Ceres Power has active commercial programs at 1kWe, 5kWe, 10kWe and 10’s of kWe. To support higher power applications Ceres has developed an innovative 5kWe-class stack design which can be used in an array to achieve higher power outputs for both stationary power and commercial vehicle applications. The stack incorporates learning from multiple development cycles and tens of thousands of hours of testing the mature 1kWe SteelCell® stack design, with several significant design improvements. This stack design has been successfully incorporated into several different customer’s systems, with outstanding electrical efficiency and mechanical robustness demonstrated, the latter facilitating the use of an SOFC stack for transportation applications.

Low-temperature SOFCs with thick-film anodes such as those developed by Ceres Power for its metal supported SOFC are inherently more resistant to REDOX cycling as a result of loss of fuel supply at temperature than traditional SOFC designs. This is due to the slow kinetics of nickel oxidation at low temperature and the anode not being the main structural support for the cell layers. High REDOX stability is essential for widespread commercial adoption of SOFC technology as the requirement to supply a protective atmosphere over the anode during uncontrolled shutdowns otherwise adds substantial cost and complexity to the system. The latest generation of Ceres Power metal supported cells show exceptional resistance to REDOX and thermal cycling, even in very aggressive accelerated tests. This has been achieved through development of the anode to achieve very robust microstructures at low processing temperatures. This paper will illustrate the current anode microstructure and the latest accelerated testing results.