A TiO2/graphene bilayer coating designed for enhanced thermal shielding performance of carbon fiber reinforced polymer

Thermal control coatings serve as a key technology for spacecraft radiative cooling in space, yet their performance faces new challenges under extreme thermal environments. If the absorbed solar heat can be efficiently transferred to this area while its conduction into internal structures is suppressed, the overall radiative cooling efficiency will be significantly enhanced. However, conventional studies on the thermal control performance of coatings have largely focused on tuning the solar absorption ratio and infrared emissivity, with insufficient attention paid to the proactive design of heat conduction behavior. Herein, we propose a bilayer coating based on TiO2 and graphene, which integrates spectral selectivity with anisotropic heat conduction to achieve efficient thermal shielding on carbon fiber reinforced polymer substrates. In this architecture, an intermediate graphene layer constructs highly efficient in-plane heat conduction pathways, while the TiO2 top-coating maintains a high infrared emissivity (εH = 0.897) and reflects about 87% of solar radiation (αs = 0.134). Anisotropic heat diffusion behavior characterized under continuous laser irradiation demonstrates that the bilayer coating exhibits outstanding lateral heat-spreading capability, leading to a notable reduction in the front-surface peak temperature and a clear improvement in thermal protection performance. This work offers a promising multifunctional coating solution for advanced thermal management in spacecraft.