Ceria-based composites are developed and considered as potential electrolytes for intermediate temperature hybrid fuel cell applications (IT-HFC). The structural properties of composite materials based on mixtures of gadolinia-doped ceria (GDC) and alkali chloride (LiCl-KCl) are analysed. The microstructure of the electrolyte is observed by scanning electron microscopy (SEM). High temperature and room-temperature X-ray diffraction allowed determining the precise structure of the composite and its regular and reversible evolution with the temperature. Finally, the electrical conductivity is determined by impedance spectroscopy and presented as a function of the electrolyte composition. The ageing behaviour after thermal cycling and at a constant temperature of 400°C shows that this material is very promising. After such conditions, conductivity of GDC/Li-K-Cl composite electrolyte is still close to 0.12 S.cm−1 at 400°C, which is more than the Li-K carbonate/GDC composite conductivity at 600°C under the same conditions.

In this paper we use cellular automata approach to model scanning electrochemical microscopy (SECM) experiments. We simulate SECM current vs distance curve for a negative feedback mode. It shows the effect of the deformation of the diffusion layer around the UME tip close to the substrate surface. We also simulate an experiment where the UME serves to locally dissolve an electrochemically inhomogeneous substrate as a consequence the substrate's geometry changes during the experiment. Our approach gives both quantitative and qualitative information on the simulated experiments. We show that simulations of real three dimensional experiments are already feasible on relatively cheap multigraphical processor unit (GPU) cards in a standard desktop workstation.

The importance of pyrochemistry is being increasingly acknowledged and becomes unavoidable in the nuclear field. Molten salts may be used for fuel processing and spent fuel recycling, for heat transfer, as a homogeneous fuel and as a breeder material in fusion systems. Fluorides that are stable at high temperature and under high neutron flux are especially promising. Analysis of several field cases reveals that corrosion in molten fluorides is essentially due to the oxidation of metals by uranium fluoride and/or oxidizing impurities. The thermodynamics of this process are discussed with an emphasis on understanding the mass transfer in the systems, selecting appropriate metallic materials and designing effective purification methods.