Effect of Al2O3 ALD coating on thermal stability of silica aerogel

Abstract

Abstract An optically transparent and thermally insulating (OTTI) silica aerogel demonstrates promising results for various solar thermal applications, particularly concentrated solar power systems. Higher system efficiency can be achieved by integrating OTTI materials by reducing heat loss at higher receiver temperature. However, the thermal stability of OTTI aerogels has been one of the limiting factors. Here, we report that Al2O3 atomic layer deposition (ALD) enhances the thermal stability of silica aerogel. The more layers of Al2O3 ALD coating on silica aerogels, the higher the thermal stability. However, more layers of Al2O3 ALD coating compromises transmittance of silica aerogel due to increasing the size of scattering centers. Therefore, optimization of Al2O3 ALD coating needs to be performed to enhance performance for a solar thermal system. The demonstrated ALD-coated aerogel provides a potential pathway to further improve the efficiency and reduce the cost of state-of-the-art concentrating solar power (CSP) systems.