D‐mannitol‐based eutectic composite phase change materials with high thermal conductivity and solar‐thermal conversion

At present, there are few kinds of phase change materials that suitable for medium temperature heat storage. Among them, sugar alcohols have broad application prospects in the heat storage at medium temperature due to their suitable phase transition temperature. In this work, eutectic phase change material (PCM) was prepared with D-mannitol as PCM and KBr as melting point modifier. Expanded graphite (EG) was used as thermally conductive support network to prepare shape-stable composite phase change material (CPCM). The prepared CPCM—10% EG/PCM has an appropriate phase transition temperature (136.88°C), high phase melting enthalpy (215.7 J/g), and good photothermal conversion (81.9%). The thermal conductivity of 10% EG/PCM reached 6.01 W/(m K), which is approximately 10 times higher than D-mannitol (0.603 W/(m K)). Because of its excellent thermal properties, the applications of CPCM in energy storage and photothermal conversion can be further broadened.