Preparation and thermal performances of microencapsulated phase change materials with a nano-Al2O3-doped shell

High-performance phase change materials (PCMs) are regarded as a promising strategy in thermal energy storage applications. However, pure PCMs exhibit some inherent disadvantages such as leakage, low thermal conductivity and poor thermal cycling stability. Herein, this work presents novel microencapsulated PCMs with nano-Al 2 O 3 -enhanced shell materials due to the high thermal conductivity and mechanical properties of nano-Al 2 O 3 . And nano-Al 2 O 3 was contributed uniformly to the shell materials through self-assembly of functional materials, forming a connected thermal conductive network for the microencapsulated PCMs and resulting in an enhancement on the thermal conductivity of the microencapsulated PCMs. Results show that thermal conductivity of the obtained microencapsulated PCMs with 8 mass% nano-Al 2 O 3 is improved up to 0.5977 W m −1  k −1 which is about 287.4% compared with that of the pure PCMs. Moreover, the obtained microcapsules enhanced by nano-Al 2 O 3 possess good phase change behavior and excellent thermal cycling stability, whose melting enthalpy can achieve 170.5 J g −1 and almost has no change after 12 times of thermal cycles.