3D printing lamellar Ti3C2T x MXene/graphene hybrid aerogels for enhanced electromagnetic interference shielding performance

Abstract

Two-dimensional (2D) transition-metal carbides and nitrides (MXenes), especially Ti₃C₂T _x nanosheets, offer high conductivities comparable to metal, and are very promising for fabricating high performance electromagnetic interference (EMI) shielding materials. Due to the weak gelation capability of MXenes, MXene/graphene hybrid aerogels were mostly studied. Among those studied, anisotropic hybrid aerogels showed excellent electrical properties in certain direction due to the intrinsic anisotropic properties of 2D materials. However, the present preparation methods for anisotropic hybrid aerogels lack freedom of geometry, and their electrical performances still have room for improvement. In this study, based on our previous work, the lamellar Ti₃C₂T _x MXene/graphene hybrid aerogels generated by 3D printing with Ti₃C₂T _x MXene/graphene oxide (GO) water-TBA dispersions demonstrated enhanced conductivity and electromagnetic interference (EMI) shielding performance. The addition of MXene deeply influenced the lamellar structure of the hybrid aerogels, and made the structure more ordered than that in the 3D printed lamellar graphene aerogels. The printed lamellar MXene/graphene hybrid aerogels achieved a maximum electrical conductivity of 1236 S m^-1. The highest EMI shielding efficiency (EMI SE) of the hybrid aerogels was up to 86.9 dB, while the absolute shielding effectiveness (SSE/t) was up to 25 078.1 dB cm² g^-1 at 12.4 GHz. These values are higher than those of most reported anisotropic MXene-based nanocomposite aerogels.

Fig. 1. Schematics of the 3D printing MXene/graphene hybrid aerogels processes. The conceived EMI shielding mechanism of the hybrid lamellar aerogels is presented in the oval inset.

Fig. 2. Rheological properties of the three kinds of MXene/GO mixed dispersions and pure GO dispersion. (a) Shear viscosity as a function of the shear rate; (b) elastic (G′) and viscous (G′′) moduli as a function of the shear stress.

Fig. 3. Scanning electron microscopy (SEM) image of (a) MGA-0, (b) MGA-1, (c) MGA-2, (d) MGA-3, and corresponding EDX elemental mappings of C, O, Ti and F in the region of the red frame for MGA-3.

Fig. 4. (a) Densities and (b) electrical conductivities of MGA-0, MGA-1, MGA-2 and MGA-3. (c) Photograph of MGA-3 on a dandelion. Structure properties of MGA-3 before (black) and after reduction (red) measured by (d) X-ray diffraction (XRD) patterns, (e) Raman spectroscopy, and (f) X-ray photoelectron spectroscopy (XPS).

Fig. 5. (a) EMI SE in the X-band of MGA-0, MGA-1, MGA-2 and MGA-3 with the thickness of 2 mm. (b) EMI SE in the X-band of MGA-3 with the thickness from 1 mm to 2 mm. (c) Contrast of the total shielding effectiveness (SE_Total), absorption shielding effectiveness (SE_A), and reflective shielding effectiveness (SE_R) at 10.2 GHz of MGA-0, MGA-1, MGA-2 and MGA-3 with the thickness of 2 mm. (d) SSE of MGA-0, MGA-1, MGA-2 and MGA-3 with the thickness of 2 mm. (e) SSE/t of MGA-3 with the thickness from 1 mm to 2 mm. (f) SSE/t value comparison between this work and the reported MXene-based anisotropic nanocomposite aerogels.