The proliferation of electromagnetic spectrum applications and increasing integration density of electronic devices have intensified electromagnetic pollution, driving demand for advanced electromagnetic interference (EMI) shielding materials. While conductive polymer composites present promising alternatives to traditional metals, attaining both exceptional EMI shielding performance and environmental sustainability remains challenging. Here, we adopt controlled mild alkaline hydrolysis to precisely engineer the surface roughness and hydrophilicity of polylactic acid (PLA) fibers, generating optimal substrates for subsequent electroless silver (Ag) deposition. The resulting Ag/PLA conductive fibers are structured into flexible films through vacuum filtration and hot-pressing. These films demonstrate remarkable electrical conductivity of 102,270 S/m, attributed to the continuous Ag coating and three-dimensional fibrous conductive network. Despite a thickness of merely 66 μm, the Ag/PLA films exhibit an ultra-high EMI shielding effectiveness (EMI SE) of 101.0 dB and a specific shielding effectiveness of 9749.4 dB·cm²/g. Notably, the films maintain military-grade EMI shielding performance (> 90 dB) after thermal cycling across a ~ 300 ^oC temperature range and 5000 bending cycles, confirming superior durability and mechanical flexibility. By synergistically coupling biodegradable PLA with recoverable Ag, this work simultaneously achieves outstanding EMI shielding performance and environmental sustainability, providing valuable insights for developing next-generation green EMI protection materials.

Carbon aerogels (CAs) have been considered potential microwave absorption (MA) materials because of intrinsic hierarchical porous structure, low density, and excellent heat resistance. However, CAs always required to be ground into micron-scale powder before being used as microwave absorbers, which will inevitably destroy the hierarchical porous structure. Meanwhile, reproducing the optimized CAs powders is difficult. Herein, CAs microspheres with in-situ mineralized TiO₂ were easily prepared via a sol–gel transition and calcination process. The uniform size of CA microspheres and the loaded TiO₂ on the skeleton of CA yield great microwave attenuation performance while guaranteeing good impedance matching performance. The obtained TiO₂/CA hybrid presented a minimum reflection loss value of −30.2 dB and a broad effective absorption bandwidth (reflection loss below −10 dB) of 6.2 GHz. The low density, MA performance, and controllable particle size make the novel TiO₂/CA hybrid promising candidates for MA applications.