Dynamic regulation in electromagnetic shielding properties of three-dimensional elastic magnetic Ni aerogels

The rapid evolution of wireless technologies and the explosive growth of electronic devices have intensified electromagnetic pollution, creating an urgent need for next–generation shielding materials. Nickel's outstanding shielding performance–rooted in its high magnetic saturation and electrical conductivity–is offset by its prohibitively high density. Here, we fabricate magnetic Ni–nanowire aerogels (NNA) by magnetic-field-guided assembly, yielding an ultra–low density of 0.026 g cm −3 lighter than conventional metal shields and most carbon aerogels. In the X–band (8.2–12.4 GHz), the NNA exhibits a shielding effectiveness (SE) of 59.2 dB, surpassing commercial standards. Its compressible, resilient structure enables dynamic tuning of electromagnetic performance; under 0 % to 80 % compression strain, the SE increases to 98.9 dB due to force-induced cross-linking of Ni nanowires, enhancing the conductive network. This lightweight design yields an absolute shielding efficiency (SSE/t) of 7560 dB·cm 2 ·g −1 , addressing the density drawbacks of metal–based shields. The NNA's high porosity also reduces reflection loss, improving absorption. This work advances lightweight, tunable electromagnetic shielding materials, integrating high SE, low density, and mechanical resilience for applications in flexible electronics and beyond.