• Energy Research

The "solid-liquid" leakage and low thermal conductivity of organic phase change materials limit their wide range of applications. In this paper, a novel carbon fiber/boron nitride (CF/BN)-based nested structure was constructed, and then, a series of poly(ethylene glycol) (PEG)-based phase change composites (PCCs) with high thermal conductivity and mechanical strength were prepared via the simple vacuum adsorption technology by employing the CF/BN nested structure as the heat conduction path and supporting material and the in situ obtained cross-linking epoxy resin as another supporting material. The thermal conductivity of the obtained PCC is as high as 0.81 W/m K, which is 7.4 times higher than that sample without the CF/BN nested structure. The support of the double skeletons confers the obtained PCCs with excellent mechanical strength. Surprisingly, there is not any deformation for PCCs under the pressure of 128.5 times its own weight during the phase change process. In addition, the phase change enthalpy of the obtained PCC is as high as 107.9 J/g. All the results indicate that the obtained PEG-based PCCs possess huge application potential in the field of industrial waste heat recovery.

Abstract Phase change materials (PCMs) can effectively absorb and release energy from the environment during the phase transition process. However, liquid phase leakage and poor energy storage occur easily at the same stage. Considering the good adhesion of polydopamine (PDA) and the high solar absorption properties of PDA and MXene, a new supporting material was prepared in this work by combining melamine foam (MF) and MXene under the action of PDA, which was used to encapsulate polyethylene glycol (PEG) to prepare a composite PCM (CPCM). Then, we experimentally studied the thermal properties of this new material. The results show that the proposed PEG/MPMF CPCM (PEG@MPMF) exhibits good heat storage properties, and the melting enthalpy reaches 186.2 J/g, which is 99.5% of that of pure PEG. The light absorption of PEG@MPMF is improved by the conjugate action of PDA and MXene. Additionally, this CPCM maintains excellent shape stability and reusability after 100 thermal cycles. Therefore, the PEG@MPMF shows great advantages in terms of heat storage and thermal management.

Abstract The risk of leakage and low thermal conductivity severely hinder the wide application of phase change materials (PCMs). In this work, the high-density polyethylene/carbon nanotubes (HDPE/CNTs) porous scaffolds were successfully fabricated via a sacrificial template method followed by the general melt blending and water solvent etching. Subsequently, a series of paraffin wax HDPE/CNTs/PW composite PCMs were obtained combined with the simple vacuum impregnation method. The obtained HDPE/CNTs porous scaffolds can effectively avoid the leakage of PW, meanwhile, the thermal conductivity and electrical conductivity of HDPE/CNTs/PW-3:7 are increased by 2.94 times and 13 orders of magnitude compared with the HDPE/PW-3:7 respectively, also, it exhibits high phase change enthalpy (153.95 J/g for melting enthalpy and 152.82 J/g for crystallization enthalpy). From the above perspectives, the HDPE/CNTs/PW-3:7 has promising potential value in the application of light-to-thermal conversion, electro-to-thermal conversion and thermal energy storage.