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A simple graphene-carbon nanotube aerogel composite was prepared. In this paper, we studied the three-dimensional (3 D) thermally conductive frameworks with different ratios of graphene oxide (GO) and carbon nanotubes (CNTs). The effects of 3 D thermal conductive frameworks with different ratios of GO and CNT on the morphology, structure and thermal conductivity of phase change composites were also studied. The results show that the 3 D thermally conductive framework has the advantages of managing the thermal conductivity of phase change composites. The obtained phase change composite with only 1 wt% of graphene-carbon nanotube aerogels showed top-quality thermal conductivity of 0.76 W/m·K. The preparation process was simple and has the advantage of environmental protection, so which was suitable for practical applications using polyethylene glycol/graphene-carbon nanotube aerogel phase change composite as energy materials, and has manageable energy conversion, storage and thermal conductivity properties. [ABSTRACT FROM AUTHOR]

A kind of paraffin@graphene/silicone rubber (SR) composite form-stable phase change material (PCM) was prepared in this paper. Paraffin@graphene phase change microcapsules were fabricated by electrostatic self-assembly method, then the microcapsules were added to the SR matrix to prepare paraffin@graphene/SR composites. The microstructure of the composite was characterized by scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) and thermal conductivity test results show that the phase change latent heat is 53.39 J g−1 and the thermal conductivity reaches 0.453 W m−1 K−1 for the composite with 30 phr paraffin@graphene microcapsules. The microcapsules enhance the thermal and mechanical properties of SR, which can be used for thermal energy storage. [ABSTRACT FROM AUTHOR]

Graphene encapsulating paraffin (paraffin@graphene) microcapsules were fabricated by electrostatic interaction-based self-assembly. An aqueous dispersion of graphene sheets charged with cation, were mixed with a water-based emulsion containning negatively charged paraffin droplet spheres to form self-assembled microcapsules. The morphology of the microcapsules was characterized by scanning electron microscope (SEM). Results show that the microcapsules with a well-defined spherical structure were prepared successfully. Differential scanning calorimeter (DSC) results indicate that the phase change latent heat are all above 200 J g−1. With a graphene mass fraction of 8 wt%, the thermal conductivity of the fabricated composites can reach 1.73 W m−1 K−1. Attributing to the interlocking of graphene with each other, the microcapsules enable lock the paraffin in the shell thus successfully avoiding its leakage during phase change process. The prepared phase change microcapsules are expected to apply in energy storage field. [ABSTRACT FROM AUTHOR]

The storage of latent heat using phase change materials (PCM) is an effective method of energy storage. In this study, silicone rubber (SR)/graphene nanoplates (GNPs)/paraffin@SiO2 phase change microcapsules (Pn@SiO2) shape-stabilized phase change materials (SSPCM) with high thermal conductivity, low leakage rate and tunable thermal management capability are prepared by method of add phase change microcapsules and thermal conductivity enhancer graphene nanoplates. The effects of Pn@SiO2 content on properties of the SR/GNPs/Pn@SiO2 (SGP) composites were investigated by scanning electron microscopy, X-ray diffraction, differential scanning calorimetry. The results show that the enthalpy of phase change composites can be adjusted from 25.6 to 78.56 J·g−1 by changing the addition amount of Pn@SiO2 microcapsules. Moreover, the effect of GNPs on the thermal conductivity of SR matrix is greater than that of Pn@SiO2 on SR, as a consequence, the thermal conductivity of SGP composites decreases with the increase of Pn@SiO2. In addition, the thermal conductivity of SGP phase change composites can also reach 0.567 W·m−1K−1 after the addition of microcapsules, which dramatically shortens the response time of the material in the application. In summary, SGP composites have promising applications in the field of thermal storage. [ABSTRACT FROM AUTHOR]