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

Abstract 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