Exploring the impact of nanostructures on specific heat in nanoparticle-doped carbonate salts via MD simulations

The enhancement of specific heat capacity in molten salts through nanoparticle addition has gained significant attention due to its potential to improve thermal energy storage efficiency. While earlier studies emphasized the role of nanoparticle dispersion, recent findings suggest that the formation of nanostructures over the surface of nanoparticles—observed through transmission electron microscopy—may be the primary mechanism behind these enhancements. In this work, molecular dynamics simulations were employed to investigate the effects of different nanoparticles—Al₂O₃, MgO, and CuO—when introduced into a eutectic mixture of Li₂CO₃-K₂CO₃ (62:38 mol%). Various nanoparticle concentrations were tested through molecular dynamics simulation, with no significant increase in specific heat capacity observed. In fact, a slight decrease in specific heat capacity was noted at higher nanoparticle concentrations. However, the incorporation of lithium-rich solid nanostructures within the molten salt led to a pronounced 18–25 % improvement in specific heat capacity. These findings highlight the critical influence of nanostructure formation in enhancing the thermal properties of molten salt nanofluids which suggests that the formation of dendritic nanostructures on nanoparticle surfaces within the molten salt is the key factor driving these improvements in specific heat capacity.