Flexible and Form-Stable Phase Change Composites Enabled by Pinecone-like Structure for Efficient Thermal Management

Phase change materials (PCMs) have become some of the most promising materials in thermal management systems. However, in practice, they are inevitably restricted by the issues of low thermal conductivity, liquid leakage, and strong rigidity. Herein, a flexible and form-stable phase change composite (PEA) with a pinecone-like structure is fabricated by a facile and scalable approach. In the PEA composite, paraffin wax (PW) is employed as PCM, styrene-b-(ethylene-co-butylene)-b-styrene triblock co-polymer (SEBS) is used as the supporting skeleton, Vaseline is used to reduce hardness, and expanded graphite (EG) and aluminum (Al) powders are used to enhance thermal conductivity. The pinecone-like EG-Al powder architecture exhibits more efficient heat transfer performance. The thermal conductivity of PEA-5 composite can reach 5.09 W m(-1) K-1, which is 28 times that of the matrix. In addition, the PEA-5 composite has good shape stability and thermal stability as well as excellent heat dissipation capability in LED modules. Interestingly, the PEA-5 composite also shows superior Joule heating performance with a saturated temperature up to 112.1 degrees C at an applied voltage of 3.5 V. This work provides insight for the rational design of highly thermally conductive and form-stable phase change composites, showing great potential for application in thermal management.