Nanocomposite phase change materials based on NaCl–CaCl2 and mesoporous silica

Abstract

The synthesis of phase change materials based on NaCl–CaCl2 molten salt mixture and mesoporous silica was investigated. The influence of mesoporous silica porosity and salt concentration on the thermal energy storage properties of the resulting materials is discussed. The nanocomposite samples were characterized by X-ray diffraction, differential scanning calorimetry, infrared spectroscopy, thermogravimetry, scanning electron microscopy and X-ray photoelectron spectroscopy. The mesoporous silica was found to act as a reactive matrix for the molten salts. Composite samples with up 95% wt. salt can be obtained and used as shape-stabilized phase change materials. The materials have heat of fusion values of up to 60.8 J g−1 and specific heat capacity between 1.0 and 1.1 J g−1 K−1. The samples exhibit thermal stability up to 700 °C and can be used for high-temperature thermal energy storage through both latent and sensible heat storage mechanisms.