Radiation‐Tolerant Bio‐Derived Carbon Aerogel Phase‐Change Composites With Bionic Gradient Insulation for Broadband Thermal Protection

ABSTRACT Conventional passive thermal materials near the Fourier conduction limit yet fail to meet combined demands for wide‑range adaptability and irradiation tolerance in extreme environments. We present a holistic strategy integrating irradiation‑resistant PCMs (Phase Change Materials) screening, pyrolysis‑stress‑driven defect engineering of hierarchical carbon aerogels, bio‑inspired g1raded architecture, and irradiation validation. Waste white radish was reprogrammed through a “collapse‐reconstruction” evolution into a tubular‐membrane hierarchical carbon aerogel (TCA1000) with ultrahigh porosity (96.86%) and mechanical stability, enabling high PCMs loading with ultra‐low thermal conductivity. Geant4 simulations identified low‐, medium‐, and high‐melting‐point PCMs for constructing CPCMs (Composite PCMs) with exceptional insulation (thermal conductivity down to 0.135 W·K −1 ·m −1 , large latent heat (339.6 J·g −1 ), and prolonged control times (4‐5.6 × TCA1000), outperforming all biomass CPCMs. The newly proposed dimensionless insulation coefficient enables cross‑system thermal insulation performance quantification and optimization. The bird‐feather‐inspired gradient layered structure effectively resolves the temperature‐range mismatch inherent in single materials, suppressing surface temperature rise by 62.3% at 350°C, achieving the optimal overall thermal‐insulation performance, while the outer LiNO 3 /mannitol synergistically enhances irradiation resistance. Irradiation tests revealed a dual mechanism—carbon skeleton protection and pore‐interface induction—enabling reverse enhancement of insulation. These CPCMs deliver a low‑cost, high‑performance solution for aerospace thermal protection, thermal therapy, infrared stealth, and cold‑chain preservation.