Controllable growth of NiCo compounds with different morphologies and structures on carbon fabrics as EMI shields with improved absorptivity

Abstract

High-conductive composite fabrics are one class of lightweight, wearable electromagnetic interference (EMI) shields. However, such materials frequently suffer from extremely high reflectivity. Carbon fabric (CF)–NiCo composites were fabricated via hydrothermal and sintering processes with CF as conductive matrix and NiCo compounds as microwave-absorbing agents, and the influences of the morphologies (nanoparticles, nanowire or/and sheets) and structures (NiCo(OH)6, NiCo2O4 and NiCo alloy) of NiCo compounds on the EMI shielding properties of CF were investigated. The results revealed that NiCo2O4 sheets not only could improve the impedance matching of CF with electromagnetic waves, but also enriched its interfacial structures, leading to the enhanced internal absorption loss and reduced surface reflection loss simultaneously. Consequently, the CF-NiCo2O4 composite in thickness only of 0.34 mm showed the shielding effectiveness of 53 dB, reflectivity of ∼0.85 and absorptivity of ∼0.15, much better than ∼45 dB, ∼0.97 and ∼0.03 for CF, highlighting the advantages of NiCo2O4 sheets in the fabrication of lightweight, green EMI shielding fabrics.