Leaf vein micronetwork engineering enhanced energy conversion strategy for C-band ultralight yet tunable microwave absorption

Lightweight materials with wide absorption capabilities, particularly in the C-band, have remained a challenge thus far. Recent research has indicated that effective absorption networks built by microfiber polarization loss can be a significant factor in increasing the effective absorption bandwidth (EAB). In this study, leaf vein-like carbon (LVC) was synthesized using an in situ blowing strategy. Taking inspiration from photosynthesis energy conversion mechanisms, a leaf veins-like hierarchical structure was created to establish an effective impedance-matching network and generate a high-density polarization region through leaf vein microfibers. This enhanced polarization relaxation effectively broadens the EAB of the LVC. At a low filling ratio of 6.3 wt%, the EAB of the LVC covers 80% of the C-band, as well as 100% of the X-band and Ku-band. Achieving such a wide EAB in the C-band, especially in the multi-band context, relies on impedance matching and optimized polarization relaxation. This work demonstrates the crucial role of leaf vein micronetwork engineering in enhancing the C-band absorption properties of carbon-based materials, thus providing a viable reference for the development of lightweight, broadband, and highly absorptive materials for electromagnetic applications.