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

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.