Controlled Fabrication of Ramie Plant Derived Magnetic Helical/Chiral Porous Carbon Fibers (Ni@CNTs@HPCFs) for Highly Efficient Microwave Absorption Performance and EAB across a Broad Temperature Range

Herein, we report a sustainable catalytic self-deposition (CSD) synthesis approach to fabricate 1D ultralightweight magnetic CNT helical/chiral porous carbon fibers (Ni_x@CNTs@HPCF_t's) that exhibit tremendous absorption performance over a broad range of temperature (700-800 °C) and magnetic contents (1.00-2.00 mmol). The synergistic impact of in situ dipping and the CSD synthesis approach enables the regulation of morphology and CNT density by encapsulating Ni nanocatalysts. Ni_x@CNTs@HPCF_t's unprecedentedly exhibit splendid absorption capabilities over broad spectrum of microwave (4.00-18.00 GHz) with efficient absorption bandwidth (EAB, RL ≤ −10 dB) and 2.00-4.50 mm thickness. Moreover, the unprecedented absorption capabilities of Ni_x@CNTs@HPCF_t's refer to their sophisticated helical/chiral structure, ultralow density, large specific surface area, CNTs, interface polarization, cross-polarization, dielectric loss by integration of 0D/1D dielectric components, magnetic loss, and well-matched impedance. Notably, Ni_1.00@CNTs@HPCF₇₀₀ at 11.92 GHz and 2.41 mm matching thickness exhibits an astronomical RL of −45.20 dB with an EAB of 10.40-18.00 GHz (7.60 GHz) covering 40% of the X band and the entire band. The EAB improves to 8.00 GHz (10.00-18.00 GHz) covering 50% of the whole Ku band at a matching thickness of 2.30 mm. Meanwhile, Ni_1.50@CNTs@HPCF₈₀₀ at just a matching thickness of 4.10 mm and 8.24 GHz gained an RL of −64.40 dB with an EAB of 4.32 GHz (6.80-11.12 GHz) covering 30% of the C band and 78% of the X band. This study opens new doors for the development of absorbers produced at a broad carbonization temperature range with comparable performance.