Integrated Design of Thermoconductive Mechanically Supporting Architectures for Manufacturing Ultra‐Stretchable Thermally Conductive Composite Phase Change Materials

ABSTRACT Phase change materials (PCMs) provide an ideal passive temperature control strategy for efficient thermal management because of their excellent energy storage density and constant heat absorption/release characteristics. However, organic PCMs, especially flexible PCMs (FPCMs), struggle to simultaneously achieve high energy storage density, excellent mechanical flexibility, and good thermal conductivity. Herein, a thermoconductive mechanically supporting architecture is designed to synergistically enhance the energy storage density, mechanical flexibility, and thermal conductivity of FPCMs. The modified boron nitride not only constructs an efficient heat conduction network but also serves as a key component of the supporting network. The prepared thermally conductive FPCMs are capable of withstanding arbitrary bending and twisting with a record‐high elongation at break up to 2191%, outperforming currently reported polymer‐based FPCMs, while possessing a high energy storage density of 145.2 J g −1 , improved thermal conductivity of 1.44 W m −1 K −1 , and outstanding thermal stability. Meanwhile, the rheological behavior endows FPCMs with excellent processing capacity, enabling them to be formed into fiber, film, and block products through traditional thermal processes such as hot pressing and extrusion. Thus, making full use of their thermal charging–discharging properties, the composites achieve efficient thermal management effects in both electronic and on‐body thermal management.