Shape-Stabilized Stearic Acid/Expanded Graphite/Chitin-Derived Carbon Phase Change Materials for Enhanced Thermal Storage Performance and Photothermal Conversion

Melting leakage and low thermal conductivity of stearic acid (SA) restrict its application in thermal storage. In this work, a shape-stabilized phase change material (ECNX/SA) with enhanced thermal storage performance and photothermal conversion is designed based on expanded graphite/chitin-derived carbon (ECNX). Thermal storage performance, including phase change temperature, enthalpy, thermal conductivity and shape stability, of ECNX/SA is investigated. With this, the influence mechanism of ECNX on the thermal storage performance is characterized via N2 isothermal adsorption–desorption, FTIR, XRD and SEM. Results show that the prepared ECN15/SA has ideal thermal storage performance, where its phase change enthalpy and thermal conductivity are 121.59 J/g and 1.573 W/(m·K), respectively, and possesses superior shape stability. Moreover, the thermal storage performance of ECN15/SA keeps stable even undergoing several thermal cycles, and its photothermal conversion is as high as 89.2%. Characterizations suggest that ECN15 with a hierarchical pore structure and a high graphitization degree to enhance the shape stability and thermal conductivity of SA. Therefore, the prepared ECN15/SA is potential using in thermal storage.