Solar Salt Thermal Storage Enhancement Through Defect Engineering

ABSTRACT Molten salts nanofluids‐based thermal energy storage systems offer a viable solution for the advancing of concentrated solar power (CSP) systems and grid peak shaving. However, further enhancement of the thermal energy storage performance of molten salts nanofluids is facing a bottleneck. Here, we report a novel defect‐engineering method that can overcome this obstacle by incorporating the oxygen vacancy (Vo) into silica nanoparticles dispersed in solar salts. By integrating experiments, DFT‐based charge analysis, MD simulations, and techno‐economic analysis, solar salt thermal storage enhancement through defect engineering is systematically investigated from microscale to system level. Unlike SiO 2 nanoparticles without V O , V O ‐engineered SiO 2 nanoparticles induce strong Coulombic interactions with molten salt ions, which can reorganize the molten salt ions into an exceptionally dense and thick compressed layer. This unique structure triples the specific heat capacity enhancement achievable with conventional nanoparticle doping, yielding a maximum increase of 56.6%. Concurrently, the thermal conductivity, dispersibility, and viscosity have also been significantly improved. System‐level analysis reveals that these integrated thermophysical enhancements directly reduce the levelized cost of electricity and increase the annual energy generation of CSP system. The established oxygen vacancy engineering provides a novel approach to underpin the potential of molten salts nanofluids‐based thermal energy storage.