A biomimetic non-woven fabric with passive thermal-insulation and active heat-recovering

The fiber-based porous materials illustrate the advantages on thermal insulation because of the limited heat convection by porous morphology and the phonon scattering at multi-scale interfaces. However, there is still space for improving thermal insulation by restricting the thermal radiation. In this work, inspired by the architecture configuration of “black body”, a double-wall carbon nanotube (DWCNT) non-woven fabric (CNF) with a gradient-pore configuration is developed to trigger the multiple reflective mechanism of infrared rays, which facilitates the infrared shielding ability, and leads to the ultra-low cross-plane thermal conductivity (k⊥) of 0.022 W m−1 K−1 at room temperature. As a result, the CNF shows a better steady and dynamic thermal-insulation performance than the commercial silica aerogel. In addition to passively insulate heat, the CNF can act as a power generator by leveraging the temperature difference to trigger the thermoelectric effect. A proof-of-concept CNF-based thermoelectric module yields a maximum output power of 42 nW at ∆T=20 K. Moreover, the CNF demonstrates the great mechanical durability, wearability and electrothermal effect, suggesting a promising candidate as a smart textile for personal thermal management.