Carbon nanotube arrays@cobalt hybrids derived from metal-organic framework ZIF-67 for enhanced electromagnetic wave absorption

Abstract

Highly efficient electromagnetic wave (EMW) absorption materials with excellent thermal management are urgently required to solve the problem of electromagnetic pollution. Herein, bead-curtain-like carbon nanotube arrays@cobalt (CNT As@Co) hybrids are designed to enhance the EMW absorption performance by using CNT As templates. After the in-situ growth of ZIF-67, CNT As@Co hybrids are successively fabricated by thermal pyrolysis of CNT As@ZIF-67 at high annealing temperature. Owing to the unique three-dimensional (3D) bead-curtain-like microstructures, the CNT As@Co hybrid pyrolyzed at 500 °C (CNT As@Co-500) with an ultra-low filler loading of 2 wt% exhibits optimal EMW absorption properties. The minimum reflection loss (RLmin) is −36.86 dB at a thickness of 5.5 mm, and the effective absorption bandwidth (RL < −10 dB) reaches as broad as 5.78 GHz with a thickness of 2.5 mm. In addition, CNT As@Co hybrids possess superior thermal conductivity (9.25 W m−1 K−1) among most similar CNT-based composites, which is conducive to the rapid dissipation of thermal energy converted from electromagnetic energy. This work provides a new paradigm for designing high-performance 3D EMW absorbers with multifunctionality in electronic devices.