Large Interlayers Spacing and Active Basal Planes Enabled Mos2/Mwcnt Composites for High-Performance Microwave Absorption

Abstract

Molybdenum disulfide (MoS2) has become a promising candidate for efficient microwave absorber due to its unique two-dimensional structure. However, the microwave absorption performance of MoS2 is still limited by the insufficient active sites and narrow interlayer spacing. Here, a combined strategy including both structure vacancies manufacturing and heteroatoms-regulating is proposed for MoS2/MWCNT composites to unlock the basal plane and then expand the interlayer spacing from 0.62 nm to 0.99 nm, thus leading to improved packing of MoS2 nanosheets and more active sites. Therefore, the tailored MoS2 nanosheets exhibit abundant sulfur-vacancies, lattice-oxygen, more metallic 1T-phase, and higher BET surface area. Such sulfur-vacancies and lattice-oxygen promote the electronic asymmetric distribution at the solid-air interface of MoS2 crystals and induce stronger microwave attenuation through interface/dipole polarization, which can be further verified by first-principles calculations. As a result, the MoS2/MWCNT composites achieve a minimum reflection loss value of -49.38 dB and an effective absorption bandwidth of 4.64 GHz at a thickness of only 1.7 mm. This structure design provides a new method for the fabrication of high-performance MoS2-based absorbers.

Keywords: Molybdenum disulfide, multi-walled carbon nanotubes, sulfur-vacancies, lattice-oxygen, high-performance absorbers