Asymmetric Silk Textile Enabling Dual‐Mode Heating for Day‐Night Adaptive Passive Personal Warming

ABSTRACT Advanced thermal management textiles are required to deliver efficient warmth across day‐night environmental fluctuations and diverse use scenarios. This requires solar absorption for daytime heat gain, together with low mid‐infrared emissivity and thermal conductivity for nighttime heat retention; however, integrating these functions into textile remains challenging. Here, this study reports an asymmetric silk textile with an embedded ceramic nanofiber network for orientation‐switchable passive personal warming. Natural silk is used as a lightweight and breathable substrate, while polydopamine‐assisted MXene assembly enables efficient photothermal conversion. Ag nanowires provide low mid‐infrared emissivity to reduce radiative heat dissipation. Meanwhile, porous SiO 2 nanofibers are introduced as a thermal decoupling layer to offset the increased thermal conductivity caused by conductive fillers, thereby reconciling low emissivity with low heat conduction. Under 1000 W m −2 solar irradiation, the fabric delivers temperature increases of 30.4°C and 18.2 °C in two heating modes, demonstrating switchable solar heat harvesting. In outdoor nighttime tests, it raises skin temperature by 6°C and 4°C, confirming effective radiative heat retention. Beyond thermal regulation, the fabric possesses hydrophobicity, breathability, UV protection, and EMI shielding, underscoring its multifunctional wearability. This work offers a structural strategy for adaptive passive thermal management textiles operating across day‐night environments.