Topological transformation strategy for layered double hydroxide@carbon nanofibers as highly efficient electromagnetic wave absorber

Abstract

Nowadays, carbon nanofibers are considered as superior candidates for electromagnetic wave absorption because of low density and high surface area. To improve the poor magnetic property of carbon nanofibers, the introduction of magnetic nanoparticles into carbon nanofibers has been proved to be an ideal strategy. Herein, novel Carbon Nanotubes/Polyacrylonitrile@NiFe based Layered Double Hydroxides composites (CNTs/PAN@NiFe-LDH) are fabricated by in-situ growth of NiFe-LDH on carbon nanotubes/polyacrylonitrile (CNTs/PAN) fibers. Impressively, layered double hydroxide can transform into nanoparticles through topological transformation process, and, the short carbon nanofibers containing NiFe alloy and NiFe2O4 particles (NiFe@CNF-x composites) are obtained at different calcination temperatures. Plenty of interfaces between the alloy promote charge separation and electrons transfer, helping to enhance interfacial polarization and related relaxation. The as-synthesized NiFe@CNF-x composites exhibit superior electromagnetic wave absorption property. Remarkably, NiFe@CNF-900 possesses a minimum reflection loss (RL) of − 49.5 dB at a relatively thin thickness of 1.4 mm, and a broad effective absorption bandwidth (RL<−10 dB) of 4.72 GHz appears at 1.5 mm. The superior microwave absorption performance is mainly ascribed to the unique structural design, appropriate impedance matching and enhanced microwave attenuation ability. The as-synthesized NiFe@CNF-x composites are promising candidates for electromagnetic wave absorption materials with low filler loading and small thickness.