Ultrahigh electromagnetic interference shielding performance of lightweight, flexible, and highly conductive copper-clad carbon fiber nonwoven fabrics

Highly conductive carbon-based fibrous materials have become one of the most sought-after components in electromagnetic interference (EMI) shielding due to their well-known properties. Herein, to fabricate exceptional shielding materials which possess desirable specific EMI shielding effectiveness (SSE) and absolute shielding effectiveness (SSE_t), lightweight, flexible, pitch-based activated carbon fiber fabrics (ACFs) that bear high surface areas and fitting thicknesses were fabricated as a carbon framework. Moreover, a thin copper layer uniformly clad on the fiber surface, as a highly conductive functional part, was deposited via electroless plating. The EMI shielding performance was studied in both low and high frequency ranges of 30 MHz-1.5 GHz and 1.5-10 GHz, respectively. The fiber-stacked foam architecture provided the assembled fabrics with a high conductivity and multiple internal reflections during shielding that manifested exceptional SSE (up to 482.2 dB cm³ g^-1) and SSE_t (11 162 dB cm² g^-1) values, which were far better than those of the pure ACFs and void-free Cu foil. Moreover, the fabrics also showed excellent pitting resistance. The prepared shielding materials can be applied to many practical and commercial applications.