Highly Stretchable Electromagnetic Interference Shielding Materials Made with Conductive Microcoils Confined to a Honeycomb Structure.

With the rapid development of flexible electronic facilities, conventional electromagnetic interference (EMI) shielding materials cannot meet the increasing demands of flexible deformation and stable EMI shielding performance. To solve this problem, in this research, stretchable conductive microcoils made from Spirulina biotemplates were confined in an orderly manner in the microgrooves of a honeycomb mold and then were sintered to form stable and conductive honeycomb networks, followed by immersion in silicone rubber to fabricate deformable EMI shielding materials. The morphologies and structures of the samples were analyzed in detail, and the conductive performance, mechanical deformation capacity, and electromagnetic (EM) characteristics of the as-prepared materials under different deformation situations were studied. The results showed that the honeycomb-structured EMI shielding materials could maintain a stable electrical conductivity and EMI shielding property under repeated stretching from 0 to 50%. Notably, the EMI shielding effectiveness of samples with 0.4 mm thicknesses increase from 23.3-26.2 to 34.3-35.7 dB in the X-band (7.8-12.4 GHz) when the tested sample is stretched to 50%, which is higher than most values of stretchable EMI shielding materials ever reported. This electrical filler particle and body structure simultaneously deforming strategy will open new routes toward the development of deformable EMI shielding materials and broaden the EM range in applications such as flexible EM protection skins, wearable EM devices, and flexible displays.