Potential Microwave Absorbers Research Articles

Three-dimensional n-MoSe2/GOx (n= 1T, 1T' and 2H) microsphere: Phase-modulation strategy and microwave absorbing mechanism

MoSe2 was identified as a potential microwave absorber, whereas its practical application was predominantly affected by the ambiguous electromagnetic wave attenuation mechanism and dielectric properties. Here, we developed a novel phase assembly-modulating strategy to prepare n-MoSe2/GOx (n = 1T, 1T' and 2H) composites, wherein phase modulation of MoSe2 exerted a gainful effect on microwave absorption properties. The unique 1T′-MoSe2 phase was first explored in microwave absorption and composited with GOx to afford advanced conductivity loss and dielectric loss. The introduction of additional interface (2H/1T or 2H/1T') and abundant unsaturated defects promote multiple polarization, the semiconductor-metal mixed phase brought in a certain magnetic loss, optimizes the electron transfer ability and adjusts the impedance matching. Consequently, 1T′-MoSe2/GOx provides the minimum reflection loss (RLmin) of −52.08 dB and the effective absorption bandwidth (EAB, RL < -10 dB) of 5.3 GHz at 10 % filler content, which is approximately 9 times that of 2H–MoSe2/GOx and nearly 5 times that of 1T-MoSe2/GOx. This paper specifically explains the reasons for the phase modulation-induced magnetic losses and provides an effective phase modulation paradigm for developing advanced transition metal disulfide (such as MoS2, WS2 and WSe2) microwave absorbers.

Investigation of structural, magnetic and dielectric properties of SrM/PEEK: A potential microwave absorber

The current study aims to investigate the effect of Polyether Ether Ketone (PEEK) on the structural, magnetic, and microwave properties of substituted M-type SrFe11.5Co0.5O12 (SrM) hexaferrite. Nanocomposites based on SrM/PEEK in ratios 4:0, 3:1, 2:2, and 0:4 were prepared by employing the micro-emulsion method. The composites were further characterized using XRD, SEM, FTIR, and VNA. XRD results exhibited a single-phase hexaferrite structure with an average crystallite size of 40 nm for pure SrM, which decreased due to increasing PEEK concentration. FESEM micrographs revealed the surface morphology and nature of the grains in the prepared nanocomposites. EDAX plots showed the presence of the constituent elements e.g., Fe, Sr, C, and O, at the respective standard energies. VSM results revealed the diamagnetic and ferromagnetic nature of PEEK and pure SrM/nanocomposite samples, respectively. FTIR spectra of SrM depicted the formation of hexaferrite due to the presence of Fe–O stretching peak at 525 cm−1. Reflection loss was found to decrease due to increasing ferrite concentration in PEEK. This indicates that SrM/PEEK composites are potential microwave absorbers for microwave applications in the X band.

Microwave absorption properties of rare earth (RE) ions doped Mn–Ni–Zn nanoferrites (RE = Dy, Sm, Ce, Er) to shield electromagnetic interference (EMI) in X-band frequency

Sol-gel auto combustion technique has been adopted to prepare RE doped Mn–Ni–Zn ferrite systems following the stoichiometry Mn0.1Ni0.7Zn0.2RE0.5Fe1.5O4 (RE = Dy, Ce, Sm and Er). The XRD patterns confirm the cubic spinel phase with the Fd3m space group and the lattice parameter and crystallite size were found to be in the range of 8.3874–8.4066 Å and 28.6–33.2 nm. The M − H data indicates the soft magnetic behaviour of present ferrite systems. The substitution of rare-earth ions in the spinel structure influences the superexchange interaction and in turn, affects the magnetic behaviour of present ferrite systems. The highest value of saturation magnetization equal to 41.2 emu/g was observed for the sample with a composition of Mn0.1Ni0.7Zn0.2Ce0.5Fe1.5O4. For all the ferrite systems studied here the real part (ε′) of complex permittivity is increasing with an increase in frequency while oscillatory nature can be found in the imaginary part (ε″). The value of ε′ found in the range of 5.421–5.856 at 8.2 GHz and it is 5.538–6.066 at 12.4 GHz. The value of ε″ is in the range of 0.092–0.104 at 8.2 GHz while it is in between 0.042 and 0.105 at 12.4 GHz. A wavy nature can be seen in the real part (μ′) of complex permeability whereas the imaginary part (μ″) is decreasing for all compositions with the increase in frequency, but shows a weak resonance peak between 9 and 10 GHz. The value of μ′ is in the range of 0.869–0.958 at 8.2 GHz and it is 0.903–0.925 at 12.4 GHz. The value of μ″ fall in between 0.269 and 0.334 at 8.2 GHz and it is in the range of 0.059–0.068 at 12.4 GHz. The shielding studies for EMI revealed that the present systems are working as microwave absorbers. The total effective shielding for all ferrite systems is in the range of 33.31–36.09 dB 8.2 GHz while it is in between 32.74 and 34.98 dB at 12.4 GHz. Under the investigation of shielding performance, it is observed that all the RE doped Mn–Ni–Zn ferrites systems studied here can effectively suppress the electromagnetic interference in X-band frequency. The ferrite system with composition Mn0.1Ni0.7Zn0.2Ce0.5Fe1.5O4 has shown a potential microwave absorber in X-band frequency.

Microwave-assisted hydrothermal synthesis of 2D/2D MoS2/Ti3C2Tx heterostructure for enhanced microwave absorbing performance

Simple and effective synthesis methods for 2D/2D heterostructure and the synergistic effect of 2D/2D composites on microwave absorbing (MWA) performance remain to be further explored and investigated. Herein, 2D/2D MoS2/Ti3C2Tx heterostructure was successfully synthesized in 30 min by a cost-effective and time-saving microwave-assisted hydrothermal method. The 2 H-MoS2 nanosheets with a thickness of 5–10 nm were homogeneously anchored on the surface of Ti3C2Tx layers, showing a tunable distribution density. Besides, the metallic properties of MoS2/Ti3C2Tx and the strong interaction between MoS2 and Ti3C2Tx, were revealed by DFT calculations, which was employed to further understand the MWA mechanism in terms of molecular dynamics. The MoS2/Ti3C2Tx composites with an optimum mass ratio of MoS2 to Ti3C2Tx (6:1) displayed the best MWA performance. The minimum reflection loss (RL) value of −41.5 dB was attained with a layer thickness of only 2.0 mm at 12.2 GHz and a 3.6 GHz maximum efficacious absorption bandwidth. The MWA mechanism of MoS2/Ti3C2Tx composites was comprehended from multiple reflections and scattering effects, synergetic effects of conductive losses and attenuation capacity, and polarization relaxations. This work provides a facile method for the synthesis of 2D/2D heterostructure, and also provides a candidate material as potential microwave absorber.

Quantitative Evaluation of Loss Capability for In Situ Conductive Phase Enhanced Microwave Absorption of High‐Entropy Transition Metal Oxides

AbstractHigh‐entropy oxides (HEO) with high stability and designability are potential microwave absorbers that serve in harsh environments. However, loss design is critical for the absorption performance of HEO due to its weak intrinsic loss capability. Inadequate loss ability results in considerable secondary reflection. Here, an in situ conductive heterogeneous phase is constructed in (Fe0.2xCo0.2Ni0.2Cr0.2Mn0.2)3O4 (x = 1–5) using a reductive circumstance, to form a dual‐phase composite. Both the ohmic and dielectric loss are enhanced as the conductive phase is introduced, while great impedance matching condition is well maintained. Hence, the composites can achieve substantial absorption across the whole X or Ku band with a thin thickness. Furthermore, key efforts are made to reveal the relationship between the absorbing performance and loss capability of an absorber. The analytical expression of the theoretical threshold of attenuation constant is derived. Based on the statistics of experimental data, the broad feasibility and practicability of the proposed theoretical threshold of attenuation constant are confirmed and discussed. Combined with both the theoretical and experimental studies, the mechanism by which the conductive phase contributes to increased absorption is also disclosed, providing an effective basis for the loss design of broadband microwave absorbers.

Remarkable microwave heating performance of MWCNTs/polypropylene composites verified by electromagnetic-thermal coupling experiment and simulation

To explore the microwave heating technology of thermoplastic materials, multiple-walled carbon nanotube (MWCNT)/polypropylene (PP) composites with mass content of MWCNT ranging from 0.5 wt% to 6 wt% had been fabricated by melt blending. The as-prepared samples were heated in a commercial microwave oven with microwave frequency of 2.45 GHz for 5 s and their surface temperatures were recorded via an infrared thermal imager. The temperature of these samples reached its highest point when the mass content of MWCNT was 3 wt% and it could be heated to 290 °C in 5 s. The composites were also characterized by scanning electron microcopy (SEM), four-point probe method and vector network analyzer (VNA) to study the morphology, electrical performance and S-parameter respectively. The dc conductivity and morphology of the sample indicates that the effective three-dimensional conductive network is formed when the mass content of MWCNT is 1 wt%, and the microwave energy is converted into heat mainly in the form of conduction loss. Microwave heating mechanism of MWCNT/PP composites was studied by EM-thermal coupling and analyzing the absorbance (A), reflectance (R) and transmittance (T) calculated by S-parameters. The simulation results of EM-thermal coupling are consistent with the experimental results. The absorbance shows the samples' absorption of microwave energy and it has the same variation trend as the samples’ temperature, which indicates that the microwave heating property of MWCNTs/PP composites can be estimated by its absorbance. Therefore, MWCNT can be considered as a potential microwave absorber for thermoplastic materials and its best content can be well estimated.

Perovskite Manganit Analysis Based on La0.7Ca0.3Mn1-xTixO3 (x=0, 0.1, 0.2, and 0.3) as Potential Microwave Absorber Material with Sol-Gel Method

&lt;p&gt;Electromagnetic wave is an energy flow in the form of electric and magnetic field as the technology development causes electromagnetic wave exposure level changes significantly and resulting an electromagnetic wave radiation that leads bad impacts on human health. In this case, manganite perovskite became an interesting topic of study that aims to produce material engineering to obtain a material with the best property as absorber. This study is based on lanthanum manganite La&lt;sub&gt;0.7&lt;/sub&gt;Ca&lt;sub&gt;0.3&lt;/sub&gt;Mn&lt;sub&gt;1-x&lt;/sub&gt;Ti&lt;sub&gt;x&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; ( and ) using sol-gel method with the with a heating temperature in the oven of 200&lt;sup&gt;o&lt;/sup&gt;C for 2 hours, calcination temperature of 600&lt;sup&gt;o&lt;/sup&gt;C for 6 hours, and sintering temperature of 1000&lt;sup&gt;o&lt;/sup&gt;C for 12 hours. The sample is characterized using X-Ray Diffraction (XRD) that shows the sample had succeeded to form single phase and had crystal cubic structure with space group p m -3 m, the substitution of Ti&lt;sup&gt;3+&lt;/sup&gt;ions did not cause the structural changes, but it was marked with the changes of lattice parameter, unit cell volume and average crystallite size. Meanwhile Vector Network Analyzer (VNA) on the frequency range 8-12 GHz shows that the sample has ability to absorb microwave until 90.16% on 10.4 GHz frequency. Therefore, the material based on lanthanum manganite La&lt;sub&gt;0.7&lt;/sub&gt;Ca&lt;sub&gt;0.3&lt;/sub&gt;Mn&lt;sub&gt;1-x&lt;/sub&gt;Ti&lt;sub&gt;x&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;has the potential as the microwave absorber material.&lt;/p&gt;

Tailoring electromagnetic responses of delaminated Mo2TiC2Tx MXene through the decoration of Ni particles of different morphologies

MXenes are widely considered as potential microwave absorbers due to their dielectric laminar structures. However, pure MXene lacks magnetic loss capability, resulting in mismatched electromagnetic parameters and unsatisfactory impedance matching conditions. Therefore, the approach of MXenes decorated with magnetic elements, inspired by dielectric-magnetic synergy, can address this obstacle. In this work, a rising delaminated Mo2TiC2Tx MXene (d-Mo2TiC2Tx) was synthesized using a combination of HF acid etching and intercalator delamination. Subsequently, spherical and flower-like Ni were loaded on d-Mo2TiC2Tx by different solvent thermal reduction pathways. The microscopic morphology indicated that the abundant functional groups on the MXene surface and the restricted interlayer space can reduce the size of Ni and promote dispersion. Moreover, the flower-like Ni-loaded MXene (NM-2) exhibits optimal absorption performance, and the minimal reflection loss value is –50.36 dB (1.4 mm, thickness) corresponding to 13.28 GHz with a bandwidth of 3.04 GHz. Meanwhile, Ni-loaded MXene can effectively absorb electromagnetic waves in the X and Ku bands (8–18 GHz) within a thickness of 2 mm, attributed to the synergistic effect of enhanced dielectric–magnetic losses, as well as matched impedance and multiple scattering from 2D/2D structures. Thus, the novel Ni/Mo2TiC2Tx powder is expected to be a very promising absorber for thin and powerful wave-absorbing materials.

Unusual dielectric properties of hollow magnesium ferrite nanospheres: a potential lightweight microwave absorber

Unusual dielectric properties of hollow magnesium ferrite nanospheres: a potential lightweight microwave absorber

Enhanced electromagnetic interference shielding effectiveness of h-BN decorated micro cube-like CaTiO3/Cu nanocomposite

Due to the balance of dielectric and magnetic losses achieved by impedance matching, combining dielectric and magnetic materials might result in potential microwave absorbers. However, some dielectric/ferromagnetic materials could also be used as good microwave absorbers, such as CaTiO3. In order to improve the microwave absorption features of CaTiO3, we fabricated two CaTiO3-based composites as CT/C (CaTiO3/Cu) and CT/C/B (CT/C/hexagonal boron nitride, h-BN). By decorating h-BN, the CT/C/B achieved a large specific area and a high total pore volume, which was beneficial to the microwave absorption performance in f = 8.2–12.4 GHz of CT/C/B compared to that of CT/C. The reflection loss (RL) was reasonably good as −15 dB for CT/C composite, while CT/C/B could reach the RL of −40 dB. Better microwave absorption dissipation features of CT/C/B compared to CT/C could result from higher electrical conductivity, attenuation constant, and lower skin depth. The presence of h-BN in the composite could also tune the total shielding effectiveness of CT/C/B to 32.5 dB, which was equal to 1.4 times compared to that of CT/C (23.5 dB).

Enhanced microwave dissipation features of BiFe0.8Co0.1Mn0.1O3/MWCNTs composite decorate of polythiophene

No magnetic loss during the absorption process is a lack of conductive polymers, while not lightweight is a drawback of magnetic materials to be potential microwave absorbers. A hybrid of magnetic material and conductive polymer is a good resolution for above issues. In this work, composites of BiFe0.8Co0.1Mn0.1O3 (BF) and multi-walled carbon nanotubes (MWCNTs, named as MW) were prepared by a hydrothermal method. Then, the in-situ polymerization method was used to decorate polythiophene on the MW/BF composites. The formation of polythiophene@MW/BF composites and their magnetic, electromagnetic properties were investigated using XRD, XPS, FE-SEM, EDS, and VNA. The composite with MW and polythiophene significantly tuned the microwave dissipation features of the polythiophene@MW/BF composites. In the measurement range of 12.4–18 GHz, the results revealed that the composite with 20 percent of MW (named as P@20 MW/BF) has a minimum reflection loss of −19 dB at frequency f = 13 GHz for a thickness of 2 mm. The maximum effective absorption bandwidth was also found for the P@20 MW/BF composite as 2.6 GHz. Enhancement in microwave absorption performance arises from the balance between magnetic loss and dielectric loss. Overall, the introduction of three-layer polythiophene/MW/BF composites provides potential microwave absorbers for application in the range of 12.4–18 GHz.

Ultrathin Self‐Assembly MXene@flake Carbonyl Iron Composites with Efficient Microwave Absorption at Elevated Temperatures

AbstractThe exploration for the potential lightweight and high efficiency microwave absorbers with thermal stability is a great challenge for researchers. More importantly, the electromagnetic parameters of absorbers at elevated temperatures are seldom studied. In this work, sandwich MXene‐Ti3C2Tx@flake carbonyl iron (MF) composites with tunable and efficient microwave absorption at elevated temperatures are successfully fabricated by an electrostatic self‐assembly method. Both the complex permittivity and permeability of the MF are strongly temperature dependent in the temperature range of 298–473 K and X band (8.2–12.4 GHz). The efficient microwave absorption of MF at different temperatures can be achieved by changing the ratio of raw materials. Specifically, at room temperature, reflection loss (RL) ≤−10 dB of MF composite covers the whole X band at 2.12 mm, while the optimum RL value is −26.3 dB at 11.81 GHz. At 373 K, the optimum microwave absorption value of the MF composite reaches up to −63 dB at 10.27 GHz and RL ≤−10 dB can cover a whole X band with a thickness of 1.52 mm. Therefore, MF composites are expected to be promising candidates as ultrathin, highly efficient, and broadband absorbing materials at elevated temperatures.

Structural, microstructural, magnetic and electromagnetic absorption properties of spiraled multiwalled carbon nanotubes/barium hexaferrite (MWCNTs/BaFe12O19) hybrid

Microwave absorption properties were systematically studied for synthesised barium hexaferrite (BaFe12O19) nanoparticles and spiraled multiwalled carbon nanotubes (MWCNTs) hybrid. BaFe12O19 nanoparticles were synthesised by a high energy ball milling (HEBM) followed by sintering at 1400 °C and structural, electromagnetic and microwave characteristics have been scrutinized thoroughly. The sintered powders were then used as a catalyst to synthesise spiraled MWCNTs/BaFe12O19 hybrid via the chemical vapour deposition (CVD) process. The materials were then incorporated into epoxy resin to fabricate single-layer composite structures with a thickness of 2 mm. The composite of BaFe12O19 nanoparticles showed a minimum reflection loss is − 3.58 dB and no has an absorption bandwidth while the spiraled MWCNTs/BaFe12O19 hybrid showed the highest microwave absorption of more than 99.9%, with a minimum reflection loss of − 43.99 dB and an absorption bandwidth of 2.56 GHz. This indicates that spiraled MWCNTs/BaFe12O19 hybrid is a potential microwave absorber for microwave applications in X and Ku bands.

3D Seed-Germination-Like MXene with In Situ Growing CNTs/Ni Heterojunction for Enhanced Microwave Absorption via Polarization and Magnetization

HighlightsBenefiting from the possible “seed-germination” effect, the “seeds” Ni2+ grow into “buds” Ni nanoparticles and “stem” carbon nanotubes (CNTs) from the enlarged “soil” of MXene skeleton.Compared with the traditional magnetic agglomeration, the MXene-CNTs/Ni hybrids exhibit the highly spatial dispersed magnetic architecture.3D MXene-CNTs/Ni composites hold excellent microwave absorption performance (−56.4 dB at only 2.4 mm).Ti3C2Tx MXene is widely regarded as a potential microwave absorber due to its dielectric multi-layered structure. However, missing magnetic loss capability of pure MXene leads to the unmatched electromagnetic parameters and unsatisfied impedance matching condition. Herein, with the inspiration from dielectric-magnetic synergy, this obstruction is solved by fabricating magnetic CNTs/Ni hetero-structure decorated MXene substrate via a facile in situ induced growth method. Ni2+ ions are successfully attached on the surface and interlamination of each MXene unit by intensive electrostatic adsorption. Benefiting from the possible “seed-germination” effect, the “seeds” Ni2+ grow into “buds” Ni nanoparticles and “stem” carbon nanotubes (CNTs) from the enlarged “soil” of MXene skeleton. Due to the improved impedance matching condition, the MXene-CNTs/Ni hybrid holds a superior microwave absorption performance of − 56.4 dB at only 2.4 mm thickness. Such a distinctive 3D architecture endows the hybrids: (i) a large-scale 3D magnetic coupling network in each dielectric unit that leading to the enhanced magnetic loss capability, (ii) a massive multi-heterojunction interface structure that resulting in the reinforced polarization loss capability, confirmed by the off-axis electron holography. These outstanding results provide novel ideas for developing magnetic MXene-based absorbers.

NiCo alloy/C nanocomposites derived from a Ni-doped ZIF-67 for lightweight microwave absorbers

In this work, we prepared NiCo alloy/C with rhombic dodecahedron structure and superior microwave absorption performance by using ZIF-67 as the raw material. The rhombic dodecahedron NiCo alloy/C was with rough particles on the surface was photographed by field emission scanning electron microscopy. By adjusting the doping amount of Ni and the temperature of pyrolysis, improved the impedance matching of NiCo alloy/C. Specifically, NiCo alloy/C exhibits a minimum reflection loss of −65.48 dB at 13.48 GHz, while the thickness is 1.63 mm. Defects introduced in the Ni doping process and the special rhombic dodecahedral structure can cause multiple loss mechanisms. Therefore, this NiCo alloy/C composite has the potential to be a potential microwave absorber material with lightweight and high microwave absorption properties.

Fe nanoparticles decorated in residual carbon from coal gasification fine slag as an ultra-thin wideband microwave absorber

Microwave absorbing materials are widely used in the defense and telecommunications industries, as means for enhancing battlefield penetration rate and improving the protection of precision instruments. The magnetic-dielectric Fe@ residual carbon from coal gasification fine slag (Fe@RC) nanocomposites were fabricated via a chemical coprecipitation and thermal annealing method, in which involve a reduction process from the Fe3O4 to Fe metal. The structure, morphology, compositions and electromagnetic parameters of the as-prepared Fe@RC materials were characterized. The obtained nano-micro scale Fe@RC shown adjusting electromagnetic parameters and outstanding microwave absorbability. The optimized reflection loss value of −47.1 dB was attained at 5.5 GHz for Fe@RC, and the effective bandwidth is 5.3 GHz (12.4–17.7 GHz) at a matching thickness of 1.5 mm. Benefit from good impedance match, special space architecture and synergistic effect between the dielectric loss from RC component and magnetic loss from Fe component, this Fe@RC materials are expected to be a potential microwave absorber. The simulated radar cross section (RCS) results prove that the Fe@RC can efficaciously reduce the microwave scatterings of the perfect electric conductor substrate at different degrees in C-, X-, and Ku-bands via adjusting the Fe@RC coating thickness. The low-cost carbon-based magnetic nanocomposites display an ultra-thin wideband microwave absorption ability and high RCS reduction performance, promoting resource utilization of the RC from coal gasification fine slag.

Preparation and characterization of nanocomposites of MoS2 nanoflowers and palygorskite nanofibers as lightweight microwave absorbers

It is an effective strategy to use clay minerals (palygorskite) to prevent the aggregation of molybdenum disulfide (MoS2) nanosheets prepared with hydrothermal process. The palygorskite/molybdenum disulfide (Pal/MoS2) nanocomposites presented notable microwave absorption performances, which can be optimized by adjusting the content of Pal. The sample with optimized composition has a minimum reflection loss (RL) of -59.91 dB at 9.92 GHz at a thin thickness of 2.28 mm, owing to the enhanced interface polarization and improved impedance matching. It is believed that the 2D hierarchically structured Pal/MoS2 nanocomposites can serve as a potential microwave absorber for practical applications.

X-band absorber carbon microbeads

Chain of carbon micro beads (CMBs) molded by interconnection of micro carbon beads were synthesized using pyrolysis of brassica nigra oil vapour at 850 °C in hydrogen atmosphere. Return loss and conductivity of arbitrarily oriented CMBs film reveals ability as a potential microwave absorber in 8 to 12 GHz range with return loss between −21 dB to −30 dB. Study of electrical resistance and EMI shielding effectiveness (SE) shows that CMBs films also has competency to obstruct the passage of microwave frequency with shielding effectiveness of −29 dB to −45 dB.

Electromagnetic characterization of Ni0.5Zn0.3Co0.2Fe2O4 bulk ceramics in the 1MHz-12GHz frequency range

In this paper, NiZnCo ferrite was produced by solid state synthesis, calcination at 1000?C and sintering at 1250?C in air atmosphere. The microstructure and phases of the sintered sample were analysed by scanning electron microscopy and X-ray diffraction, respectively. The magnetic properties of the ferrite were evaluated by magnetization and magnetostriction measurements. The complex magnetic permeability and complex permittivity were also measured between 1MHz-12GHz and the reflection loss (RL) was calculated in the 100MHz-12GHz frequency range. The results show that the ferrite sample presents magnetostrictive behaviour and a saturation magnetization of 71 Am2/kg. Complex permittivity measurements indicate that the material has dielectric behaviour in the whole frequency range studied, with "? varying between 7-40, and magnetic behaviour in frequencies between 1MHz-5GHz. The minimum RL was found at frequencies between 2.4-3.3GHz and the calculated RL value for a thickness of 3mm was lower than ?10 dB in frequencies between 2.3-7.3GHz. These results indicate potential application as microwave absorber in the S band.

Spider web-like carbonized bacterial cellulose/MoSe2 nanocomposite with enhanced microwave attenuation performance and tunable absorption bands

It is essential to manufacture microwave absorbers with strong absorption as well as tunable absorption bands at a low filler content. However, it remains challenging for pure biomass material to reach this goal without loading other components. MoSe2, as a transition metal chalcogenide with semiconductor properties, has emerged as a potential microwave absorber filler. Herein, bacterial cellulose (BC)-derived carbon nanofibers/MoSe2 nanocomposite was fabricated and phosphoric acid was used to dope phosphorus in BC, in which MoSe2 microspheres were dropped on the BC network like a dew-covered spider web. This unique network structure enhances conductive loss and multiple reflections of the incident wave. The collocation of BC and MoSe2 is helpful to impedance match and introduces interfacial/dipolar polarization loss; moreover, the P-doping of BC helps to tune the absorption bands. Overall, the optimal reflection loss of undoped one reaches −53.33 dB with only 20 wt.% filler content, whose main absorption peaks focus on X-band. Interestingly, after the P-doping of BC, the main absorption peaks move to Ku-band and the optimal reflection loss gets stronger (−66.84 dB) with the same filler loading. Strong absorption and tunable absorption bands can be realized, and thus wide frequency range is covered. This work is expected to enlighten future exploration of biomass carbon materials on high-performance microwave absorption materials.