Preparation and Thermal Properties of a Novel Highly Thermally‐Conductive Composite Phase Change Energy Storage Material Based on Sodium Acetate Trihydrate‐Acetamide/Expanded Graphite

Abstract Rising living standards intensify the demand for maintaining temperatures within the human thermal comfort range, yet concurrently exacerbate building energy consumption issues. Building energy use dominates total energy consumption and shows a marked upward trend. Thus, enhancing the energy efficiency of heating systems and reducing their energy demand is critically important. In this study, sodium acetate trihydrate (SAT) was utilized as the phase change material (PCM), acetamide served as the temperature regulating agent, sodium chloride acted as the nucleating agent, and sodium carboxymethyl cellulose (CMC) functioned as the thickening agent. Through combined experimental and characterization, the thermal energy storage and release mechanisms of PCMs were systematically investigated. By integrating modified PCM was integrated into expanded graphite (EG) to develop a composite phase change material (CPCM). SEM and pore structure analysis confirmed the successful incorporation of the modified PCM into the pore structure of EG. The physical interaction between the two materials was verified through XRD and FT‐IR spectroscopy. After 150 hot and cold cycles, the melting temperature variation of CPCM was less than 3%, and the melting enthalpy loss was only 0.3 J/g, indicating excellent thermal stability. The results demonstrate that CPCM exhibits excellent temperature regulation.