Grid structure phase change composites with effective solar/electro-thermal conversion for multi-functional thermal application

Abstract

Phase change materials (PCMs) have high energy storage density and stable phase transition temperature, and are one of the most promising thermal storage and management materials. However, the PCMs’ shape instability, poor light absorption, low electrical and thermal conductivity seriously hinder their multi-functional application. Herein, a three-dimensional carbon aerogel with grid structure, large porosity, and hierarchical porous structure was prepared from resource-rich plant straw for supporting PCMs. Polyethylene glycol (PEG) as thermal energy guest was encapsulated into carbon aerogel by simple vacuum impregnation. The obtained PEG/carbon aerogel composites show high loading rate of PCMs（＞97%), high thermal storage density (＞185 J g−1), stable shape, and effective solar/electro-thermal conversion. The grid structure carbon aerogel as efficient thermal and electron transfer pathways guarantee effective solar/electro-thermal conversion of composites. PEG encapsulated in each lattice as a thermal functional unit realizes the thermal storage and management. Especially, grid-structure composites realized fast and uniform electro-thermal conversion and storage under low voltage. This work provides a feasible, economic, and large-scale preparation strategy for the multi-functional PCMs. The multi-functional composites have broad application prospects in solar energy capture and storage, waste power recycling, building energy saving, smart thermal management and so on.