Excellent microwave response derived from the construction of dielectric-loss 1D nanostructure

Abstract

Increasing efforts have recently been devoted to the artificial design and function of nanostructures for their application prospects in catalysis, drug delivery, energy storage, and microwave absorption. With the advantages of natural abundance, low cost, and environment friendliness, a one-dimensional (1D) MnO nanowire (MW) is the representative dielectric-loss absorber for its special morphology and crystalline structure. However, its low reflection loss (RL) value due to its thin thickness limits its wide development and application in the microwave absorption field. In this work, artificially designed MnO@AIR@C (MCs), namely, 1D hollow carbon nanotubes filled with nano-MnO, were designed and synthesized. It is found that the RL value of the MC is almost lower than -10 dB. Furthermore, the RL value was able to achieve -18.9 dB with an effective bandwidth (-10 dB) of 5.84 GHz at 2.25 mm. Simultaneously, the dielectric and interfacial polarization became stronger while the impedance matching was much better than in the single MWs. Hence, the rational design and fabrication of micro-architecture are essential and MC has great potential to be an outstanding microwave absorber.

Facile Preparation of Snowflake‐Like MnO2@NiCo2O4 Composites for Highly Efficient Electromagnetic Wave Absorption

“…To date, many kinds of 1D nanomaterials have been successfully appliedf or highly efficient EMW absorption purposes.F or example, 1D porous Ni@C nanorods wered emonstratedt oh ave ag ood EMW absorbing capability and the minimum RL at 10.8 GHz reached À26.3 dB for amatching thickness of 2.3 mm. [16] It can be concludedf rom the above results that the EMW absorbing performance can be deeply influenced by the morphology of MnO 2 .When the morphology of MnO 2 was prepared with a1 Ds tructure, its EMW absorbing performance should be significantly improved. [16] Ad ozen years later,M nO 2 is still employed as good dielectric loss EMW absorbing material due to its low cost, great heat endurance, and simple preparation method.…”

“…demonstrated that MnO 2 @NiMoO 4 composites with hierarchical structures displayed a good EMW absorbing capability and the minimum RL value of the MnO 2 @NiMoO 4 composites was found to be −31.4 dB at 11.2 GHz for a matching thickness of 3.0 mm. A MnO 2 @AIR@C composite was also fabricated; the RL value reached −18.9 dB with a matching thickness of 2.25 mm, and an available band width (−10 dB) of 5.84 GHz could be achieved . It can be concluded from the above results that the EMW absorbing performance can be deeply influenced by the morphology of MnO 2 .…”

“…[5,14] In addition, 1D nanostructures could provide al ong carriage channel for current consumption, [15] which is conducive to conductionl oss and also beneficial to enhance the EMW absorptioncapabilities. [16] Ad ozen years later,M nO 2 is still employed as good dielectric loss EMW absorbing material due to its low cost, great heat endurance, and simple preparation method. To date, many kinds of 1D nanomaterials have been successfully appliedf or highly efficient EMW absorption purposes.F or example, 1D porous Ni@C nanorods wered emonstratedt oh ave ag ood EMW absorbing capability and the minimum RL at 10.8 GHz reached À26.3 dB for amatching thickness of 2.3 mm.…”

“…Manganese dioxide (MnO 2 ) is deemed to be a typical EMW dielectric material, which was firstly employed in the EMW absorbing field as early as 2006 . A dozen years later, MnO 2 is still employed as good dielectric loss EMW absorbing material due to its low cost, great heat endurance, and simple preparation method.…”

Microwave Absorption of Crystalline Fe/MnO@C Nanocapsules Embedded in Amorphous Carbon

“…One feasible approach is introduction of transition metal oxide MnO to construct heterogeneous crystalline–amorphous Fe–C-based composition with nanoscale architectures and further boost microwave absorption performance. The MnO in size of nanoscale contributes to produce more dipoles and dipolar relaxation [ 34 ]. MnO dispersed on the surface of graphene can also weaken the stacking interactions [ 35 ].…”