Heterostructure-engineered diamond-graphene composites for high-performance and stable electromagnetic wave...

Designing electromagnetic wave absorbing (EWA) materials that simultaneously deliver strong attenuation and withstand harsh environments remains a major challenge due to long-standing trade-offs between dielectric performance and structural robustness. Here, we report a heterostructured diamond-graphene composite synthesized under moderate high-pressure and high-temperature conditions, in which multilayer graphene is embedded within a nanodiamond framework through covalently bonded interfaces. This architecture enables modulation of the sp³/sp² hybridization ratios, yielding tunable dielectric responses, improved impedance matching, and multiple, synergistic energy-dissipation pathways. The optimized composite achieves a minimum reflection loss of -60 dB and an effective absorption bandwidth of 4.0 GHz. Simultaneously, the material exhibits exceptional environmental tolerance, including high thermal stability, reliable absorption at high temperatures, large fracture toughness, and enhanced corrosion resistance, which originates from the mechanically interlocked diamond/graphene networks and chemically stable carbon interfaces. Our results establish a scalable heterointerface-engineering strategy for constructing multifunctional carbon architectures that unify strong microwave attenuation with outstanding thermal, mechanical, and chemical durability, offering a promising platform for next-generation EWA materials suitable for harsh or demanding environments.