Review of carbon-based electromagnetic shielding materials: film, composite, foam, textile

Carbon-based electromagnetic shielding materials are reviewed in terms of their performance, type, and preparation. They include film, composite, foam, and fabric with particular attention on their frequency selectivity ascribed to the periodic structure. The SE/t, referring to shielding effectiveness per unit thickness (dB/mm), and SSE, referring to shielding effectiveness per unit density (dB center dot cm(3)/g), are summarized. The main conclusions of this work are as follows: (1) large area film shows higher SE/t, in which carbon nanotube (CNT) film is endowed with the most attractive value (19,500 dB/mm); materials containing CNTs achieve higher shielding efficiency, ascribe to a high specific surface area, have a greater length-diameter ratio, and a one-dimensional continuous-oriented structure; (2) notably, frequency selectivity based on varied period structures has been widely studied; the method includes multilayer structure/printing/cutting/backfilling and, especially, woven fabric; (3) favorable shielding effectiveness is attributed to the shielding material's intrinsic electrical conductivity and structural integrity. Based on these developments, this paper aims to provide some valuable data, highlight the important research direction, and advance the development of carbon-based electromagnetic shielding materials.