Modifications of microencapsulated phase change materials: Supercooling suppression, thermal conductivity enhancement and stability improvement

As "micro-containers" for thermal energy storage, microencapsulated phase change materials (MEPCMs) have gained attention due to their high heat storage density, high surface area-to-volume ratio and excellent leak resistance. However, MEPCMs still face some challenges, such as high supercooling degree, low thermal conductivity, and poor stability. In recent research, many modification methods for MEPCMs have been proposed to address the aforementioned issues. Herein, this paper first provides an overview of the current challenges in various applications of MEPCMs. Then, it introduces and compares modification methods to address these issues, including the loading of nanomaterials, modification of shell/core materials, modification of the inner and outer surfaces of the shell, and the creation of internal thermally expandable voids. These methods have shown notable effects in suppressing supercooling, enhancing thermal conductivity, and improving stability in MEPCMs, demonstrating significant potential for future applications. Finally, challenges, development directions, and problem-solving methods are proposed.