Electrospinning Machine| TiN nanofiber metacomposites for efficientelectromagnetic wave absorption: Insightson multiple reflections and scattering effects

Prof. Gong Chunhong from Henan University: TiN Nanofiber Metacomposites for Efficient Electromagnetic Wave Absorption

The rapid development of information technology has led to severe electromagnetic pollution, making electromagnetic wave (EMW) absorbing materials increasingly important. Faced with the challenges posed by electromagnetic pollution, researchers have been actively exploring high-performance EMW absorbing materials for different environmental temperatures. Considering the thermal effects associated with electronic devices and specific high-temperature applications, the study and development of high-temperature EMW absorbing materials are particularly urgent. EMW absorbing materials with stable performance across a wide temperature range are crucial for both military operations and civilian life.

Recently, Prof. Gong Chunhong’s team at Henan University published their latest research, "TiN Nanofiber Metacomposites for Efficient Electromagnetic Wave Absorption: Insights on Multiple Reflections and Scattering Effects", in the Journal of Materials Science & Technology. The researchers synthesized flexible titanium nitride/zirconia/carbon (TiN/ZrO2/C) fiber membranes via electrospinning and pre-oxidation-nitridation processes. The TiN/ZrO2/C fibers were then cut into functional units and controllably composited with polydimethylsiloxane (PDMS). This novel metacomposite structure played a significant role in inducing multiple reflections and scattering of incident EMW (Fig. 1).

Fig. 1: Schematic of the experimental process.

Based on the flexibility of the TiN ceramic composite membrane, metacomposites with a unique hierarchical structure were prepared. This approach effectively extended the transmission path of EMW. When the functional unit content was as low as 10.0 wt.%, the composite exhibited excellent EMW absorption performance across a wide temperature range (298 K–573 K), attributed to the synergistic effects of superior impedance matching and attenuation capability. Additionally, at 453 K, the minimum reflection loss (RL) reached -51.7 dB, with an effective absorption bandwidth (EAB) of 2.3 GHz. This study provides a reference for designing high-attenuation EMW absorbing materials under complex high-temperature conditions.

Fig. 2: SEM, TEM, and elemental mapping of TiN/ZrO2/C fiber membranes.

As the carbon content increased, the fiber diameter gradually decreased (Fig. 2). Simultaneously, due to the higher polyvinylpyrrolidone (PVP) content in the precursor spinning solution, the viscosity increased, resulting in fibers with higher aspect ratios. Moreover, the interconnected TiN/ZrO2/C fibers formed a rich 3D conductive network, providing more opportunities for EMW interaction and enhancing conductive loss. The distinct heterogeneous interfaces among the three phases also generated abundant interfacial polarization, improving polarization loss.

Fig. 3: Electromagnetic parameters and loss tangent of TiN/ZrO2/C metacomposites.

Fig. 4: Dielectric constant trends and Cole-Cole curves of TiN/ZrO2/C metacomposites.

As shown in Fig. 3, the dielectric constant and loss tangent gradually increased with higher filler content, owing to the rich heterogeneous interfaces and dipole-active sites, which enhanced polarization effects. On the other hand, more TZC fiber membranes in the PDMS matrix facilitated the formation of local conductive networks, further boosting conductive loss. The metacomposites in Fig. 4 exhibited clear Cole-Cole semicircles, indicating significant polarization relaxation loss. The Cole-Cole curves of TZC3-15 and TZC3-20 also showed obvious straight tails, primarily due to increased conductivity from higher filler content.

Fig. 5: Electric field vector distribution simulations of TZC metacomposites

To further explore the interaction mechanism between TZC metacomposites and EMW, the electric field vector distribution at 10 GHz was simulated. In Fig. 5(b), the electric field intensity around the TZC functional units varied significantly, indicating strong EMW interaction and multiple reflections between the TZC membranes, which facilitated EMW dissipation. However, when the number of TZC membranes in the periodic unit was low, the EMW absorption capability was insufficient due to reduced interaction (Fig. 5(a)). Conversely, excessive TZC membranes weakened the electric field intensity due to impedance mismatch, causing EMW reflection at the surface (Fig. 5(c)). Thus, orderly unit design is an effective strategy for tuning absorption performance.

Fig. 6: RCS simulations of TZC3-10 at different temperatures.

To evaluate the far-field EMW absorption characteristics of TZC membranes at different temperatures, the radar cross-section (RCS) of TZC3-10 at 10 GHz was simulated (Fig. 6). The 3D RCS simulations (Figs. 6(a)–(d)) showed significantly reduced scattering signals, confirming the excellent EMW absorption of TZC membranes. At 473 K, TZC3-10 exhibited the lowest RCS signal, indicating optimal absorption. The 2D RCS curve (Fig. 6(e)) further verified this, with nearly all values below -10 dBm² across the detection range.

Fig. 7: Reflection loss, impedance matching, and attenuation constants of TiN/ZrO2/C metacomposites.

As shown in Fig. 7, TZC3-10 demonstrated the best EMW absorption performance, achieving a minimum RL of -51.7 dB at 10.2 GHz and 453 K due to synergistic impedance matching and attenuation. Its periodic ordered structure effectively extended the EMW transmission path and induced multiple reflections and scattering. By rationally adjusting the filler ratio of functional units, high-efficiency EMW absorbing materials can be obtained.

Aimed at complex high-temperature environments, this study focuses on the development and optimization of absorbing materials. By designing metacomposites with periodic structures to enhance EMW absorption, it provides valuable insights for related fields.

Paper Link: https://doi.org/10.1016/j.jmst.2025.01.046