MnCu-MOF-Derived Fan-Deployed Carbon Frameworks: Size-Dependent Broadband Microwave Absorption and Thermal Insulation

Developing multifunctional materials that integrate efficient microwave absorption and high-temperature thermal insulation remains a critical challenge for next-generation electromagnetic protection systems, particularly in aerospace and extreme environments. This study presents a fan-structured metallic framework MOF with temperature-triggered transformation: the precursor’s “closed-fan” architecture expands into an open hierarchical structure upon calcination, facilitating multiscale electromagnetic dissipation and tortuous heat conduction pathways. The optimized composite achieves an exceptional effective absorption bandwidth (EAB) of 6.4 GHz at 2.0 mm thickness and remarkable thermal insulation, maintaining a rear surface temperature of ∼360.8 °C after 120 s under 1000 °C heating. Structural characterizations reveal that the fanlike architecture promotes multiple electromagnetic wave reflection/scattering and retards heat transfer, while size-dependent absorption behavior confirms that reduced segment dimensions enhance impedance matching and dielectric loss via increased interface polarization. This work establishes a stimuli-responsive structural transformation paradigm, where hierarchical architecture–chemical composition synergy enables simultaneous optimization of microwave absorption and thermal insulation, offering actionable insights for advanced composites in harsh-environment protection.