Two-Dimensional Nanosheets of Titanium Carbonitride Ti₃CNT_x MXene for Microwave Absorption in the X and Ku Bands

Abstract

New types of microwave absorption (MA) materials are urgently demanded in military radars and communication satellites working in the frequency of 8−12 GHz (X band) and 12−18 GHz (Ku band). However, it remains a challenge to make a material completely satisfy the MA requirements in the whole frequency bands. Here, two-dimensional (2D) Ti 3 CNT x nanolayered flakes were produced by HF etching of the Ti 3 AlCN precursor and exhibited an attractive MA performance in the X and Ku bands. The minimum reflection loss (RL) of Ti 3 CNT x was −41.36 dB at 11.76 GHz with a sample thickness of 1.94 mm. Meanwhile, an effective absorption band (EAB) of 4.24 GHz (in the frequency range 13.76−18 GHz) was achieved when the sample thickness was 1.5 mm. Spin-polarized density functional theory calculations confirmed that Ti 3 CNT x possesses magnetic moments. The magnetic moments mainly originate from the severe asymmetric spin of electrons of Ti atoms located between N and functional groups induced by the unpaired electrons of N atoms. The synergetic effects of dielectric loss and magnetic loss mechanisms contribute to the MA performance of Ti 3 CNT x . 2D nanosheets of Ti 3 CNT x are a promising candidate for MA applications.

Hollow Core–Shell Fe3O4@PPy Nanocomposites with Tunable Microwave Absorption Frequencies and High Reflection Loss

“…The RCS value of the nanocomposite can be obtained through Equation 3. 30,31 In Equation 3, λ represents the wavelength of the incident microwaves, S is the surface area of the nanocomposite, and E i and E s represent the magnitudes of the electric fields for the incident and scattered microwaves correspondingly. The simulation employed a plane wave with vertical polarization, where "e" and "h" denote the electric and magnetic fields, respectively, and the microwaves propagate in the negative direction of the Z-axis.…”

Comparative Effects of Hydrazine and Thermal Reduction Methods on Electromagnetic Interference Shielding Characteristics in Foamed Titanium Carbonitride MXene Films

“…[25,26] It may also manifest localized magnetic moments that adjust the impedance matching and activate the magnetic loss mechanism. [27] Therefore, it holds the promise to enable a remarkable synergistic contribution of dielectric loss and magnetic loss. In this regard, some potential has been unlocked for its electromagnetic wave absorption capability.…”

“…In this regard, some potential has been unlocked for its electromagnetic wave absorption capability. [25][26][27][28][29] Notably, when incorporated into various polymer matrices, Ti 3 CNT x MXene shows stronger interfacial interactions and improved compatibility owing to its abundant surface terminations with additional -NH groups, thereby resulting in efficient dielectric modulation, especially at low-weight fractions. [30] Furthermore, distinct advantages are evident in its sample preparation, treatability, and mechanical response.…”

“…Compared to Ti 3 C 2 T x , while ensuring safer synthesis conditions, Ti 3 CNT x enables enhanced exfoliation and tighter stacking. [27,30,31] These features offer a more convenient delamination process in the initial stage and, subsequently, a feasible process to produce an integrated morphology with enhanced mechanical properties. [32] With enhanced reactivity and primary bond stability (due to the presence of nitrogen), [33,34] Ti 3 CNT x demonstrates high treatability and postprocessing versatility.…”

“…For instance, annealed Ti 3 CNT x (up to 350 °C) rendered the highest reported SE (116 dB) at comparable thicknesses, plausibly due to its layered, metamaterial-like structure. [24,27] Likewise, a suitable chemical treatment enables the surface engineering and the morphology alternation of MXene films. As evidence, H 2 SO 4 efficiently enhanced the SE of Ti 3 C 2 T x by inducing surface charge polarization and creating micro-sized wrinkles through the formation of Ti vacancies.…”