Innovative spongy attapulgite loaded with n-carboxylic acids as composite phase change materials for thermal energy storage

Abstract

Spongy attapulgite (s-ATP), a novel nanoporous material with a three-dimensional porous network, was assembled from purified attapulgite micropowder (p-ATP) and used as a host material to prepare composite form-stable phase change materials (PCMs). The average pore diameter of the spongy ATP network was measured as 13.3 nm and the pore walls consist of thin layers constructed of ATP nanorod-like crystals. Due to the capillary forces of spongy ATP, n-carboxylic acids can be easily absorbed into ATP samples by the vacuum method. The effects of the three-dimensional network structure of the supporting material on the thermal properties of the composites were investigated. The thermal energy storage, thermal stability and durability of the composite PCMs were tested by differential scanning calorimetry and thermogravimetry. The PCM/spongy ATP composites had a high heat storage capacity between 72.57 and 82.36 J g⁻¹, corresponding to a mass fraction of n-carboxylic acids between 36.60% and 37.71%. The PCM/spongy ATP composites exhibited excellent thermal stability and durability, and may have great potential for renewable energy storage applications.