Biomimetic pangolin-scale sustainable cellulose-based composite paper serves as a multifunctional platform for...

Cellulose, as an abundant and sustainable carbohydrate polymer, has emerged as a promising platform for radiative cooling due to the intrinsic infrared activity of its C-O-C and CC vibrational bonds. However, conventional cellulose material face critical challenges in cooling efficiency, environmental durability, and scalable fabrication for outdoor portable applications. Herein, inspired by the "flexible and tough" structure of pangolin scales, a biomimetic, scalable, and high-performance ultra-lightweight radiative cooling ZnO@ZIF-8 carboxymethylated fiber paper (ZZCFP) fabricated via in-situ growth of porous core-shell ZnO@ZIF-8 (ZZ) within a carboxymethylated cellulose paper (CFP) was developed. The tight binding and uniform dispersion of ZnO@ZIF-8 with CFP endow it with a hierarchical pore structure, simultaneously enhancing light scattering and thermal emission effects, leading to outstanding solar reflectance (98.2%) and high thermal emittance (96.5%). In addition, ZZCFP exhibits remarkable mechanical robustness (16.8 MPa tensile strength) along with superhydrophobicity, UV resistance, and biodegradability. Outdoor testing demonstrates a sub-ambient cooling effect of 15.4 °C under direct sunlight. Practical applications in automotive engine and temporary strawberry storage achieved cooling of 10.6 °C and 11.7 °C, respectively. This work provides a scalable and sustainable pathway to high-performance, durable radiative cooling materials, establishing a design paradigm for multifunctional cellulose-based composites in sustainable thermal management.