Preparation and application of three-dimensional filler network towards organic phase change materials with high performance and multi-functions

Abstract

Organic phase change materials (OPCMs) are a kind of energy storage materials and receive lots of attention for their outstanding strengths, such as high phase change enthalpy, finite phase change temperature range, and good chemical and physical stability, and can be utilized in various applications, for example, waste heat recovery. However, the small thermal conductivity (less than 0.5 W/(m·K)) and unstable morphology of OPCMs in melting state largely restrict their applications. Directed at these, different modification methods are designed or invented, such as physical blending, microencapsulation, spinning and pre-constructing three-dimensional (3D) filler network, etc. Thereinto, the method of pre-constructing 3D filler network to modify the OPCMs is a highly effective way to fabricate the composite phase change materials (PCMs) having a large thermal conductivity, a high phase change enthalpy and an excellent encapsulation ability at a low filler content. Besides, this method also has some other merits, for example, easy to handle and convenient for large-scale production. To date, various strategies, such as physical mixing, ice-templated method, hydrothermal and chemical reduction, carbonization, chemical vapor deposition (CVD), chemical crosslinking and template method, etc. have been developed to prepare the 3D filler network for the composite PCMs. In this review, we will focus on preparation methods and applications of 3D filler network, which are mainly used in the composite PCMs. Especially, we will discuss the effects of microstructures of 3D filler network on the performances of the composite PCMs and the advantages and disadvantages of different methods. Moreover, the advanced applications of the composites OPCMs are also summarized. Finally, current challenges and opportunities of utilizing the 3D filler network for the composite PCMs are proposed.