Robust Core–Shell C@C/SiO ₂ Nanofibers for Superior Electromagnetic Shielding Withstanding Repeated Joule Heating and Multiple Bending

Flexible electromagnetic interference (EMI) shielding inorganic materials integrated with thermal management remain highly desirable for next‐generation wearable electronics in protective applications. Here, a core–shell carbon@carbon/silica (C@C/SiO 2 ) composite nanofiber is fabricated via a coaxial electrospinning and subsequent carbonization. By tailoring the carbon content in the core and the carbonization temperature, the resulting C@C/SiO 2 nanofiber achieves a gradient interfacial architecture. Benefiting from the continuous C core and the groove‐like C/SiO 2 shell, the C@C/SiO 2 nanofiber exhibits high flexibility, superior EMI shielding, and reliable thermal control performance. The optimized conductivity and impedance matching endow the composite membrane with an outstanding EMI shielding effectiveness of 30.8 dB and a high shielding effectiveness/thickness value of 133.7 dB mm −1 at only 0.23 mm thickness, corresponding to a shielding efficiency exceeding 99.92%. Moreover, it delivers ultrafast and stable Joule heating behavior, reaching ≈220 °C within 10 s at a low voltage of 10 V and a maximum temperature of 250 °C. Meanwhile, the membrane also maintains structural and functional stability even after 8000 bending cycles and 100 thermal shock cycles. This work provides a tunable route toward lightweight, durable, and highly efficient EMI shielding membranes for applications in flexible electronics and harsh‐environment protection systems.