Asymmetric Structural Design for Absorption-Dominated Electromagnetic Interference Shielding Composites

Excessive electromagnetic pollution caused by electromagnetic waves can interfere with the normal use of electronic devices or cause unnecessary damage to human health. Although conductive polymer composites (CPCs) are used to replace traditional metals as an effective strategy for managing undesirable electromagnetic waves, CPCs have a non-negligible trade-off in the enhancement of electromagnetic interference (EMI) shielding effectiveness and absorption coefficient because of their reflection-dominated EMI shielding mechanism. Therefore, to alleviate secondary electromagnetic pollution, absorption-dominated EMI shielding composites with asymmetric structures are urgently needed. Recently, asymmetric structural designs for absorption-dominated EMI shielding composites have advanced significantly, but have seldom been summarized and discussed in detail. Consequently, this review first systematically summarizes the current progress of absorption-dominated EMI shielding composites with asymmetric structures after a brief clarification about the necessity and configuration of asymmetric structure design. Afterward, various absorption-dominated EMI shielding composites with asymmetric fiber, layered, porous, composite structures are systematically described. Besides, the versatility of absorption-dominated EMI shielding composites with asymmetric structures is briefly introduced. Finally, the current challenges and prospects are proposed to guide future advancement in the EMI shielding field.