A medium-temperature, metal-based, microencapsulated phase change material with a void for thermal expansion

Abstract

Microencapsulated phase change materials (MEPCMs) have great application prospects in medium/high temperature thermal energy storage. However, it might rupture due to the thermal expansion of PCMs during the phase change process, which greatly reduces its service life and seriously restricts its development. Herein, an innovative technique to encapsulate PCMs was presented. A thermal expansion void was successfully constructed inside the MEPCMs by “double-layer coating, sacrificial inner layer” method to accommodate volume expansion of PCMs. Scanning electron microscope (SEM), differential scanning calorimeter (DSC), Powder X‐ray diffraction (XRD) and other characterizations revealed the microstructure and thermal performance of MEPCMs. The results showed that MEPCMs with thermal expansion void exhibit better thermal performance and longer thermal cycle life than that of MEPCMs without thermal expansion void. Based on this method, the rupture problem of MEPCMs caused by thermal expansion of PCMs during phase change process can be solved thoroughly. Furthermore, “double-layer coating, sacrificial inner layer” method is also suitable for microencapsulation of other metals and it provides a new perspective for medium or high temperature metal microencapsulation.