Flexible N-Doped Carbon Nanofiber-Polydimethylsiloxane Composite Containing La_0.85Sr₀.₁₅CoO_3−δ Nanoparticles for Green EMI Shielding

High-performance green electromagnetic interference (EMI) shielding materials are in great demand due to the growing need for portable electronic devices and high speed digital communication devices. Developing high-efficiency, lightweight, and flexible EMI shielding materials for practical applications is still a major challenge. Herein, we demonstrate a facile approach for fabricating thin and lightweight N-doped carbon nanofibers (CNFs) containing La 0.85 Sr 0.15 CoO 3−δ (LSCO) nanoparticles (NPs) (LSCO-CNFs) through electrospinning followed by heat treatment. CNFs incorporated with 25 wt % LSCO NPs (LSCO-CNFs-25) exhibited high electrical conductivity (2.1 S cm –1 ) and high EMI shielding effectiveness (EMI SE) of 45 dB with a low thickness (0.08 mm) in X-band, K u -band, and K-band (8.2–26.5 GHz). The material showed an absorption-dominated shielding mechanism due to formation of a 3D electrically conductive network, high interfacial polarization arising from the presence of LSCO NPs in CNFs, and the porous and layer-by-layer structure of CNFs. The flexible polydimethylsiloxane (PDMS) composites of LSCO-CNFs were prepared by hand lay-up methods for enhancing the mechanical properties and hydrophobicity. The LSCO-CNFs-25 PDMS composites exhibited a high EMI SE of 45.6 dB with a thickness of 0.62 mm. The LSCO-CNFs-PDMS composites are ideal for fabricating lightweight, thin, waterproof, flexible, and high-performance EMI shielding materials.