Carbon Black/Graphene Composite-Decorated Basalt Fiber Fabric for Electromagnetic Wave Absorption

Lightweight and flexible electromagnetic wave (EMW) absorbing materials have become increasingly essential for modern electronic equipment operating in complex environments, addressing the growing challenges of EM pollution. This study fabricated an EMW absorbing coating using nano carbon black (CB) and graphene sheets (GSs). The synergistic combination of two-dimensional flakes and zero-dimensional spherical structures established a “point-to-surface” contact configuration, forming a more efficient electron transport network and thereby enhancing interfacial contact efficiency. Furthermore, a flexible absorbing fabric was developed by integrating this coating with basalt fiber fabric (BFF) via a doctor-blading process. The basalt fiber helps to optimize impedance matching, while its unique interwoven structure promotes multiple internal reflections and refractions of EMW, significantly improving the absorption performance. With a CB/GSs filler content of 20%–25%, the fabric achieved optimal EMW absorbing properties. In the X-band, the reflection loss (RL) reached −38.75 dB with a maximum effective absorption bandwidth (EAB) of 3.53 GHz. In the Ku-band, the minimum RL was −32.9 dB with a maximum EAB of 3.36 GHz. Compared to plain basalt fiber fabric, the absorbing fabric exhibits both higher mechanical strength and excellent hydrophobic properties, enabling it to adapt to more complex application environments. This work provides a suitable approach for the industrial development of EMW absorbing materials.