Biomass-derived 3D magnetic porous carbon fibers with a helical/chiral structure toward superior microwave absorption

Herein, a catalytic self-deposition (CSD) strategy is proposed to build 3D magnetic porous carbon fibers with a complex helical/chiral structure (MHPFs) toward ultralight and low-frequency microwave absorption unprecedentedly. Different from energy-intensive chemical vapor deposition (CVD) method, the binary composition of cobalt-encapsulated carbon nanotube arrays (CNTAs) and hierarchical pore structure are manipulated by adjusting the CSD technology without exogenous carbon and reducing atmosphere. Micro-/nano-scale structures, 0D/1D integration effects, dielectric/magnetic loss mechanisms, and extraordinary 3D helical/chiral configuration endow MHPFs with remarkable microwave absorption properties. The minimum reflection loss (RLmin) of MHPFs-900 (900 stands for the carbonization temperature) at a low frequency (6.3 GHz) reaches astronomical -61.08 dB. The effective absorption bandwidth (EAB, RL < -10 dB) ranges from 5.4 GHz to 7.5 GHz at a loading of 5%. Notably, at a matching thickness of 2.00 mm, the ultrawide EAB covers 6.2 GHz (11.6-17.8 GHz), while the RLmin exceeds -30.06 dB. Moreover, even with an ultralow filler loading of 2.5%, the absorber still exhibits satisfactory RLmin and broad EAB of -45.04 dB and 4.5 GHz (8.2-12.7 GHz). The results might shed light on the economical and high-producing preparation of advanced microwave absorption materials. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

A catalytic self-deposition (CSD) strategy was proposed to fabricate 3D magnetic porous carbon fibers with a complex structure, which exhibited remarkable microwave absorption properties. The unique structure and composition of the fibers resulted in exceptional performance in terms of minimum reflection loss and effective absorption bandwidth, showing potential for the economical preparation of advanced microwave absorption materials.