Recent Advances and Opportunities in Nanomaterial‐Based Absorption‐Dominant High Green Index Electromagnetic Interference Shields

Rapid advances in electronics has led to a significant increase in electromagnetic radiation from electronic devices, posing potential threats to human health. Developing lightweight, high‐performance, and green electromagnetic interference (EMI) shields is crucial for mitigating electromagnetic pollution. EMI shielding research over the last decade has provided numerous alternatives to metal shields using carbon nanotubes, graphene, MXenes, etc. However, these shields are mostly reflection‐dominant, just like metals, due to their high conductivity, offering hardly any remedy to the secondary pollution issue. Thus, the research focus has shifted to reduce the reflection and develop absorption‐dominant EMI shields. A green index, defined as the ratio of absorption over reflection, must be well over 1 and preferably even as high as 10. This article provides an in‐depth review of the theoretical foundations of EMI shielding, highlighting various loss mechanisms, along with recent advances in absorption‐dominant EMI shields. Various strategies to reduce reflection through better impedance matching, including foam and aerogels, semiconductor fillers, magnetic fillers, gradient conductivity shields, conductivity‐magnetic dual gradient, segregated structures, printed shields, metastructures and others are discussed . Finally, design strategies of absorption‐dominant shields are analyzed, and current challenges and potential pathways are outlined to guide future advancements and facilitate practical implementation.