A Sustainable and Low-Cost Route to Design NiFe₂O₄ Nanoparticles/Biomass-Based Carbon Fibers with Broadband Microwave...

Carbon-based microwave-absorbing materials with a low cost, simple preparation process, and excellent microwave absorption performance have important application value. In this paper, biomass-based carbon fibers were prepared using cotton fiber, hemp fiber, and bamboo fiber as carbon sources. Then, the precise loading of NiFe₂O₄ nanoparticles on biomass-based carbon fibers with the loading amount in a wide range was successfully realized through a sustainable and low-cost route. The effects of the composition and structure of NiFe₂O₄/biomass-based carbon fibers on electromagnetic parameters and electromagnetic absorption properties were systematically studied. The results show that the impedance matching is optimized, and the microwave absorption performance is improved after loading NiFe₂O₄ nanoparticles on biomass-based carbon fibers. In particular, when the weight percentage of NiFe₂O₄ nanoparticles in NiFe₂O₄/carbonized cotton fibers is 42.3%, the effective bandwidth of NiFe₂O₄/carbonized cotton fibers can reach 6.5 GHz with a minimum reflection loss of -45.3 dB. The enhancement of microwave absorption performance is mainly attributed to the appropriate electromagnetic parameters with the ε' ranging from 9.2 to 4.8, and the balance of impedance matching and electromagnetic loss. Given the simple synthesis method, low cost, high output, and excellent microwave absorption performance, the NiFe₂O₄/biomass-based carbon fibers have broad application prospects as an economic and broadband microwave absorbent.