Flexible, Highly Thermally Conductive and Electrically Insulating Phase Change Materials for Advanced Thermal Management of 5G Base Stations and Thermoelectric Generators

Abstract

Thermal management has become a crucial problem for high-power-density equipment and devices. Phase change materials (PCMs) have great prospects in thermal management applications because of their large capacity of heat storage and isothermal behavior during phase transition. However, low intrinsic thermal conductivity, ease of leakage, and lack of flexibility severely limit their applications. Solving one of these problems often comes at the expense of other performance of the PCMs. In this work, we report core–sheath structured phase change nanocomposites (PCNs) with an aligned and interconnected boron nitride nanosheet network by combining coaxial electrospinning, electrostatic spraying, and hot-pressing. The advanced PCN films exhibit an ultrahigh thermal conductivity of 28.3 W m−1 K−1 at a low BNNS loading (i.e., 32 wt%), which thereby endows the PCNs with high enthalpy (> 101 J g−1), outstanding ductility (> 40%) and improved fire retardancy. Therefore, our core–sheath strategies successfully balance the trade-off between thermal conductivity, flexibility, and phase change enthalpy of PCMs. Further, the PCNs provide powerful cooling solutions on 5G base station chips and thermoelectric generators, displaying promising thermal management applications on high-power-density equipment and thermoelectric conversion devices.

Minireview on Design of Flexible Composite Phase Change Materials to Various Energy Applications: Progresses and Perspectives

“…As an emerging composite material, flexible composite PCMs have become a research hotspot in recent years because of their ability to withstand certain deformations. − In general, flexibility is a concept related to rigidity that emphasizes the deformability of materials with linear elasticity, inelasticity, or plasticity in the stress–strain relationship. Compared with SS-CPCMs, flexible composite PCMs generally have the characteristics of being bendable, foldable (or twistable), and stretchable, and their properties remain unchanged after a certain deformation. , On the basis of the application scenarios of the flexible composite PCMs, the selection of suitable support materials and flexible strategies is crucial for flexible composite PCMs.…”

“…Therefore, the relationship between heat storage capacity and the mechanical properties of flexible composite PCMs needs to be explored to determine its application scenario. Numerous approaches have been employed to develop flexible composite PCMs (Table ), and their preparation processes mainly include the physical adsorption of porous materials and spinning. ,,− However, systematic reviews summarizing these methods are still lacking in the literature.…”

Synthesis and Properties of Dynamic Crosslinking Polyurethane/PEG Shape-Stable Phase Change Materials Based on the Diels–Alder Reaction

“…Making full use of solar energy and recycling waste heat to reduce the global energy consumption, the thermal management technology has significance for our life. Especially, with the rapid development of 5G communication and battery fast-charging technology, the power density of electronic devices has increased dramatically, and the higher heat flux density and thermal failure have become the primary problem restricting their performance and lifetime. , Phase change materials (PCMs) have an advantage in storing and releasing a great amount of latent heat through the phase transition process in a reversible way, so applying PCMs to the thermal management system can effectively reduce the temperature fluctuations and improve the products’ work life. , Therefore, it is an ideal choice for storing thermal energy and improving energy efficiency.…”

Thermal conductivity and closed-loop recycling of bulk biphenyl epoxy composites with directional controllable thermal pathways

“…Thermal management is a critical issue for miniaturized electronics and electric motor component since heat accumulation will cause thermal fatigue and reduce the lifetime. [1][2][3][4] Polymer materials with high thermal conductivity have been widely used for thermal management owing to their low cost, light weight, and easy processing. 5,6 Epoxy resins, the most common thermosetting polymers, have the desired characteristics, such as sufficiently low thermal expansion coefficient, strong adhesion to dissimilar materials, sufficient mechanical robustness, and moisture absorption resistance.…”