Advances in molten salt-based nanofluids: Thermal property enhancement and applications in CSP and power systems

Molten salts have shown great promise in various applications, particularly in concentrated solar power (CSP) systems, heating systems, and high-temperature electrothermal energy storage. However, advances in thermal energy systems demand enhanced material properties, particularly higher specific heat capacity (SHC) and thermal conductivity (TC). Doping nanoparticles (NPs) has proven effective in enhancing the thermophysical properties of molten salts, and deeper understanding of its strengthening mechanism can help develop more impressive strategies. This paper provides a state-of-art review of the most used preparation methods of salt-based nanofluids and advanced techniques for measuring their thermophysical properties, not only outlining the recent experimental and simulation progress on SHC and TC enhancement but also summarizing the underlying enhancement mechanisms. Moreover, progress on the viscosity variety of molten salt nanofluids is systematically summarized by focusing on the primary influencing factors. Future research directions are also discussed, including the synergistic enhancement effects of multi-component nanofluids and surface charge regulation strategies. At last, the practical applications and potential challenges of molten salt-based nanofluids in CSP systems are explored.