Input of atomic layer deposition for solid oxide fuel cell applications

The development of a new generation of solid oxide fuel cells (SOFCs) operating at lower temperatures with competitive performances requires the use of high-quality thin layers, either as electrolytes, electrodes or interlayers, such as catalysts, diffusion barriers, bond or protective layers. Atomic layer deposition (ALD) is a sequential chemical vapour deposition (CVD) technique allowing processing of one mono-atomic layer after another, conformal, adherent and homogeneous nano-scaled films which are often crystalline as-deposited without the need of high-temperature annealing treatments. Moreover, the scalability of ALD offers an important prospect for industrial applications. In this work, the literature dealing with ALD applied to SOFCs is thoroughly analysed, showing the present achievements as well as the numerous advantages of this technique. New developments for the future are currently in progress extending the potential use of ALD to other high-temperature devices such as proton electrolyte fuel cells, high-temperature water electrolysis, HTWE (with reversed SOFC-type systems) and molten carbonate fuel cells (MCFCs).