High-Performance, Strain-Stable Electromagnetic Shielding Materials Enabled by Magnetic Elastic Fiber Networks Pinning Liquid Metal.

Abstract

Stretchable electromagnetic interference (EMI) shielding materials are critical for the reliability of wearable electronic devices in complex electromagnetic environments. However, achieving compatibility between ultra-thinness, high shielding efficiency (SE), and excellent dynamic stability remains a major challenge in this field. Here, an ultrathin elastic EMI shielding film (TPU/Fe-LM) is developed by leveraging the magnetoelectric synergy effect and a pinning-interlocking mechanism between ferromagnetic elastic nanofiber networks and the embedded liquid metal (LM), achieving high EMI SE and excellent strain stability. The ultrathin film, with a thickness of 85 µm, exhibits an average EMI SE exceeding 70 dB across a broad frequency range of 0.1 MHz to 40 GHz, with only a 2.59% variation under 100% tensile strain. This superb EMI SE per unit thickness (SSE = 1225 dB mm^-1 @ 100% strain) ranks among the highest reported for stretchable EMI shielding films, highlighting the exceptional application potential. As a proof of concept, the EMI shielding film is integrated into a stretchable capacitive strain sensor for dynamic and static force sensing, achieving a 50-fold enhancement in angle resolution for robotic motion monitoring. This research paves the way for stretchable EMI shielding materials and offers valuable guidance for enhancing electromagnetic protection in wearable electronics.