Biomimetic Janus Fabric with Ice Plant Bubble‐Like Cell Structure for Passive Daytime Radiative Cooling and Energy Conversion for Wearable Applications

ABSTRACT Smart textiles require advanced sensing capabilities, yet existing sensor‐integrated fabrics suffer from poor breathability, brittleness, and thermal vulnerability, restricting large‐scale deployment. Herein, inspired by the epidermal bubble‐like cell structure of ice plants, we developed an ultra‐lightweight Janus fabric, with a polyelectrolyte membrane as the key component—its inherent high stability, excellent ion conductivity, and good compatibility endow the fabric with superior structural flexibility and functional synergy. This design integrates passive daytime radiative cooling (PDRC) and sensing functions, retaining breathability and directional moisture transport. Notably, the polyelectrolyte membrane‐enhanced fabric achieves 9.86°C sub‐ambient cooling (101 W m − 2 net cooling power) under 1 sun intensity, 100% accurate motion monitoring, and stable triboelectric output (10 V stable output under 10 N constant force), along with exceptional durability (1000 folding cycles), recyclability, and antibacterial activity. Owing to the prominent advantages of structural innovation, excellent performance, and strong practicality, this study can not only be effectively extended to other inorganic particle systems (e.g., SiO 2 , boron nitride) but also holds broad application prospects in wearable electronic devices, flexible robots, and intelligent sensing systems.