2D TiN/graphene metacomposite for photosynthesis-inspired EM modulation and multi-stage attenuation

Metacomposites offer a transformative approach to simultaneously optimize impedance matching and dielectric loss in microwave absorption materials (MAMs), especially under thermal fluctuations. Inspired by broadleaf foliage, we design sub-wavelength regime flexible TiN/reduced graphene oxide (RGO) membranes (TRMs) as “microwave-absorbing leaves”. A critical geometric threshold emerges from the ratio of membrane lateral size (L) to incident wavelength (λ_m). When L/λ_m < 0.1, minimal interfacial reflection enables efficient wave transmission. At L/λ_m ≈ 0.1, TRMs trigger multi-scattering and cascaded attenuation, which boosting dielectric loss while maintaining near-unity impedance matching. In contrast, when L/λ_m>0.1, electromagnetic waves are reflected at the macroscopic interface, resulting in severe impedance mismatch, poor wave penetration, and markedly reduced absorption. Leveraging this sub-wavelength scale control, optimized TRMs-2 achieves an outstanding minimum reflection loss (RL_min) of −57 dB at only 1.1 wt.% filler loading and a broad effective bandwidth of 3.8 GHz. It also exhibits robust thermal stability from 298 to 573 K. This work establishes a clear link between two-dimensional (2D) mesoscale geometry and electromagnetic dissipation, providing a biomimetic paradigm for lightweight, thermally stable MAMs that break the traditional trade-off between impedance matching and attenuation.