Collaborative passive cooling of impact-hardening interfaces enabled by nacre-mimetic design

Balancing thermal management with mechanical buffering is critical for protecting outdoor devices and expanding their application scenarios. Here we propose a nacre-mimetic strategy that synergistically improves passive cooling and impact resistance through brick-and-mortar component regulation, surpassing numerous advanced high-performance composites. Dynamic crosslinking within the composition imparts non-absorption in specific spectral bands and strain-rate-dependent impact hardening. The as-designed composite exhibits a thermal anisotropy ratio of 44.47 and remains nonflammable under an 873 K flame for 1 h, releasing low-carbon gaseous products. It achieves solar reflectance and mid-infrared emittance of 0.97 at 393 K, translating to urban cooling energy savings exceeding 40%. The composite resists projectile penetration at 50 m s^-1, and closed-loop recycling retains thermo-mechanical performance comparable to the pristine counterpart. Building on these attributes, we develop a thermo-mechanically coupled protective sandwich configuration featuring high volume resistivity and a low dielectric constant. This design delivers a maximum cooling effect of 20.5 K and dissipates 97.90% of the kinetic impact force in overheated outdoor devices. Life-cycle assessment quantifies a low environmental footprint. Collectively, this nacre-inspired paradigm illustrates sustainable multi-physics coupling management and holds strong promise for safeguarding outdoor devices in extremely harsh environments.