Scaphium scaphigerum/graphene hybrid aerogel for composite phase change material with high phase change enthalpy and high thermal conductivity for energy storage

Abstract

Based on the disadvantages of the low thermal conductivity and easy leakage of the organic phase change energy storage material, Scaphium scaphigerum/graphene hybrid aerogel (SGA) with sparse porous structure was prepared by the template method and used as a thermally conductive reinforcing material to fabricate PEG forming composite PCMs of SGA/PEG. The results show that the three-dimensional pore structure of the SGA is composed of extremely thin graphene sheets interwoven and connected to each other. The EDA reducing agent can effectively remove the oxygen-containing functional groups, allowing the graphene sheets to re-adhere to the SC soft stencil and continuously aggregate, stack and self-assemble, resulting in thermally stable SGA. DSC result shows SGA/PEG composite has excellent overall thermal performance, especially SGA/PEG-8 with a latent thermal storage energy of 166.11 J/g, which is 99.35 % of that of pure PEG, and remains 99.20 % even after 100 heating-cooling cycles. The XRD, FT-IR and Raman spectroscopy results show that there is no chemical reaction in the SGA composite with PEG and that it is physically bonded. The TGA results show that the SGA can effectively conduct heat from the surface of the sample, showing a beneficial effect on the thermal stability of the composite. The SEM results directly demonstrate that the three-dimensional pore structure of the SGA is uniformly wrapped by PEG and that the surface of the lamellae is relatively smooth, without any significant accumulation of PEG. Furthermore, the shape-stable SGA/PEG exhibited a high thermal conductivity of 1.0621 W/(m K) which was enhanced to 378 % relative to pure PEG. This novel strategy offers enlightening prospects for the preparation of composite phase change materials with good thermal storage properties, thermal conductivity and thermal stability for a wide range of applications in energy storage.