On the anticorrosion mechanism of molten salts based nanofluids

Abstract

With renewables as the main candidate for future energy sources, efficient energy storage is considered a key to unlock its full potential. In this context, thermal energy storage (TES), particularly molten salt-based TES, is considered as an efficient, simple and a low-cost option. One of the main drawbacks for this technology is the corrosion of vessels storing the salt at elevated temperatures. Recently, the addition of nanoparticles has been reported to be able to mitigate the corrosivity of molten salts by several independent groups. However, no convincing explanation has been established so far as to why such behaviour takes place. In this work, we attempt to give a new insight into anticorrosion performance of molten salts dopped with nanoparticles (molten salts nanofluids) both experimentally and through Molecular Dynamic simulations. XPS-depth profiling, SEM-EDX and XRD experiments together with macroscopic and atomistic modelling were used in this work and the results suggest that the diffusion of nanoparticles into construction materials at high temperatures is one of the corrosion mitigation mechanisms of molten salts nanofluids. This new finding allows the explanation of some of the reported corrosion results and hence paves the way for a new anticorrosion strategy for molten salts and other high-temperature applications.