Enhanced Specific Heat Capacity in Molten Salt Nanofluids: The Role of Nanoscale Structural Modifications and Interionic Interactions

Abstract

The incorporation of nanoparticles into molten salts has shown promise for enhancing their thermal energy storage capabilities, particularly through increases in specific heat capacity (SHC). While the formation of secondary salt nanostructures around nanoparticles has been observed, the underlying mechanisms for SHC enhancement remain debated. This study employs Molecular Dynamics (MD) simulations to investigate the SHC of nanoscale regions of lithium carbonate (Li2CO3), potassium carbonate (K2CO3), and sodium carbonate (Na2CO3) with systematically reduced interionic bond lengths, mimicking the dense packing observed in experimentally reported nanostructures. Our simulations reveal a significant increase in SHC in these constrained nanoscale domains compared to their bulk counterparts, directly correlating this enhancement with stronger Coulombic interactions and altered vibrational dynamics arising from the compressed structures. These findings provide atomistic insights into the contribution of nanoparticle-induced structural modifications to the improved thermal properties of molten salt nanofluids for advanced energy storage applications.

Keywords: Thermal energy storage, molten salt, nanostructure, specific heat capacity, molecular dynamics simulation, nanoparticle