Kapok fiber-derived hollow carbon structure decorated with hydrangea-like MoS2 as sustainable and efficient electromagnetic wave absorbing composite fibers

Biomass-derived materials (BCMs) have drawn intensive attention for electromagnetic (EM) wave absorption because of their high carbon content and unique structure. In this work, kapok fiber (KF) was used as a BCM to prepare kapok carbon fiber (KCF) for EM waves absorption. To optimize the impedance matching characteristics, hydrangea-like MoS2 was decorated on the KCF surface through a simple hydrothermal method. The high aspect ratio and unique hollow structure of KCFs provide large specific surface areas. The decoration of hydrangea-like MoS2 further increases the roughness of the surface, facilitating scattering and multiple reflections of EM waves. Furthermore, the enormous number of heterointerfaces and defects in MoS2/KCF composite fibers generates interfacial and dipole polarizations. Consequently, the MoS2/KCF composite fibers exhibit a remarkable minimum reflection loss (RLmin) of -58.0 dB at 12.0 GHz and a wide effective absorption bandwidth (EAB) of 4.8 GHz. This work provides a guideline to utilize BCMs as sustainable, efficient, and lightweight EM wave absorbing materials.