Microwave-assisted rapid growth of titania on lignin-derived bowl-like carbon microspheres for improved electromagnetic wave absorption and corrosion resistance

Microwave-assisted hydrolysis enables rapid growth of TiO 2 on lignin-derived carbon. • The optimal TiO 2 /40 C composite exhibits greatly improved corrosion resistance. • The TiO 2 @40 C shows broadband absorption (EAB = 4.30 GHz) at a thickness of 1.29 mm. Carbon-based electromagnetic wave (EMW) absorbents have attracted considerable attention owing to their low density and tunable dielectric properties. However, excessive dielectric loss often leads to impedance mismatch, thereby compromising EMW attenuation performance. To address this challenge while preserving the lightweight nature of carbon materials, lignin-derived bowl-like porous carbon microspheres were integrated with TiO 2 through microwave-assisted rapid hydrolysis to construct dual-dielectric TiO 2 @C composites. The unique bowl-like porous structure provides an interconnected conductive framework with multiple scattering pathways, whereas the uniformly decorated TiO 2 regulates the dielectric response and introduces abundant heterogeneous interfaces. By tailoring the carbon-to-Ti ratio, the optimized TiO 2 @40 C composite achieves a minimum reflection loss of −20.56 dB at 2.02 mm, and an effective absorption bandwidth of 4.30 GHz at a thin matching thickness of 1.29 mm. Structural and electromagnetic analysis indicate that the enhanced EMW attenuation originates from the synergistic contributions of improved impedance matching, conduction loss, and interfacial polarization of the composite. Meanwhile, the introduction of TiO 2 improves the corrosion resistance of the composite, suggesting enhanced environmental stability. This work presents a feasible strategy for cost-effective biomass-derived carbon-based composites with dual-dielectric compositional design towards high-performance and corrosion-resistant EMW absorbents.