CNT cluster arrays grown on carbon fiber for excellent green EMI shielding and microwave absorbing

Carbon fiber (CF) is a flexible shielding material with excellent electrical conductivity, thermal stability and mechanical properties, which is crucial to solve electromagnetic pollution problems. However, its application in green electromagnetic interference (EMI) shielding is hampered due to high secondary reflection. Herein, we proposed a method to selectively grow CNT cluster arrays on the CF surface for tunable green EMI shielding and microwave absorbing. The density of CNT cluster arrays can be manipulated by controlling of CF surface functional groups in the preparation route of metal-organic framework derived Co-doped CNTs. The CF/CNTs cluster array composites exhibit excellent electromagnetic wave absorbing performance, with an effective absorption bandwidth of 4.4 GHz with a matching thickness of 1.38 mm, which can be extended to full frequency band from 2 to 18 GHz through metastructure design. The green EM shielding index is greater than 12 in the whole frequency range from 2 to 18 GHz, with the maximum value up to 351. The strategy developed here provides a valuable guide for the preparation of electromagnetic functional materials with multilevel hierarchical structure. [Display omitted] •A novel method to selectively grow CNT cluster arrays on CF surface is proposed.•The CF/CNT cluster arrays exhibits an ultrathin absorption with EAB of 4.4 GHz.•High-efficiency green EMI shielding is realized with gs > 12 covering full frequency band.