Development of high conductivity zirconia anodes for solid oxide fuel cells
In recent years much development has focused on solid oxide fuel cells (SOFC) as a source of clean electric power, because they are able to convert a wide variety of fuels and because they do so with such high efficiency (40-60% unassisted, up to 70% in pressurized hybrid system) compared to engines and modern thermal power plants (30-40% efficient). SOFC technology dominates competing fuel cell technologies because of the ability of SOFCs to use currently available fossil fuels, thus reducing operating costs. Also, SOFCs are attractive as energy sources because they are clean, reliable, and almost entirely non-polluting. Because there are no moving parts and the cells are therefore vibration-free, the noise pollution associated with power generation is also eliminated.
During the past 5+ years, IPMS has been conducting research to radically improve the ionic conductivity in zirconia electrolytes and the mechanical properties of solid oxide fuel cells (SOFC). In particular, their work has focused on nano-sized SOFC materials sourced from Europe’s solitary zircon-sand deposit which is located in Ukraine. Their research has indicated an improvement by a factor of five in the ionic conductivity of zirconia may be achieved by combined use of Ukrainian 10-mol.% Sc2O3 – 1-mol.% CeO2 – stabilized zirconia powder, and electron beam physical vapour deposition (EB-PVD) technique for the dense electrolyte and diffusion barrier layers to be deposited on porous Ni-ZrO2 anode.
The higher conductivity is the result of true nano-sized zirconia powder, 10-15 nm in comparison with 100-200 nm of its commercial analogues. Additionally, another gain is achieved with EB-PVD electrolyte films consisting of nano-diameter filaments. The combination of these two features allows SOFC cells with a five-fold increased ionic conductivity of the electrolyte and interdiffusion layer and subsequently a more than 30% increase in efficiency of SOFC cells at and below 600 °C using low-temperature cathodes developed by IPMS.
In order to bring the technology a step closer towards application in the clean energy sector, IPMS need UB to educate and train them in i) characterization of zirconia powders using Hg porosimeter and IS Impedance Analyser and ii) long term performance tests to evaluate the SOFC with zirconia anodes. This will enable IPMS to have a deeper understanding of the behaviour of the new SOFC electrolyte materials under typical operating conditions in order to prove their high performance, reliability and durability. This refers to both anode substrate and metal substrate cell designs. In this context, the pilot project will addresses cost efficiency, ease of manufacture, fuel cell stack reliability and durability.