Design of sea urchin-like metal oxide nano-porous spheres for improving the thermo-physical properties of nitrate salts

In recent years, the global demand for clean, sustainable and efficient energy has increased significantly. To meet this need, it is important to explore renewable and environmentally friendly energy sources. Concentrated solar power (CSP) plants have emerged as a promising solution. The performance of CSP systems is highly dependent on the thermal properties of the heat transfer fluids (HTFs) used. Recent studies have shown that nanoparticle enhanced molten salts can provide outstanding thermophysical properties such as improved specific heat capacity, wider operating temperature range and enhanced thermal stability. In this study, sea urchin-shaped manganese oxide nanoparticles were integrated into conventional molten salts to improve their thermal performance. These nanostructures were successfully synthesized with the desired morphology by two different approaches, namely in situ growth on the salt surface and wet chemical synthesis. A two-step crystallization protocol was used to ensure homogeneous distribution and stable integration of the nanoparticles into the salt matrix. This study aims to reduce the melting point, improve thermal conductivity, specific heat capacity and minimize agglomeration. According to DSC and TGA analysis, a decrease of 4°C in solid to solid transition temperature and a 30.5% increase in decomposition temperature are observed. This wider thermal range results in increased sensible heat storage within the same system and eventually improves thermal efficiency. These improvements show that the nanocomposite offers significant advantages over traditional molten salts and has great potential for advanced CSP applications.