No abstract

Wearable electronics with miniaturization and high-power density call for devices with advanced thermal management capabilities, outstanding flexibility, and excellent permeability. However, it is difficult to achieve these goals simultaneously due to the conflict between high thermal conductivity and permeability and flexibility. Here, we report an approach to fabricate flexible, breathable composites with advanced thermal management capability by coating the boron nitride nanosheets (BNNSs) layer with high thermal conductivity on the grids of patterned electrospun thermoplastic polyurethane (TPU) fibrous mats. The composite exhibited a significant enhancement of thermal conductivity and preserved instinctive breathability simultaneously. When the composite was integrated into flexible devices, its saturating operating temperature dropped significantly compared to that of pure Ecoflex packaging. Moreover, the surface temperature fluctuation was less than 0.5 °C during more than 2000 cycles bending-releasing process. Finally, a prototype to fabricate wearable electronics with advanced thermal management capability was proposed.

Due to its great potential applications in thermal management, heat control, and quantum information, phononics has gained increasing attentions since the first publication in Review of Modern Physics 84, 1045 (2012). Many theoretical and experimental progresses have been achieved in the past decade. In this paper, we first give a critical review of the progress in thermal diodes and transistors, especially in classical regime. Then, we give a brief introduction on the new developing research directions such as topological phononics and quantum phononics. In the third part, we discuss the potential applications. Last but not least, we point out the outlook and challenges ahead.