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As 5G technology advances, so does the prevalence of harmful electromagnetic waves, and as a result, researchers have been progressively interested in developing materials that can absorb microwaves. So, it's become desirable to fabricate unique microwave absorbent materials (MAMs) to mitigate the negative effects of electromagnetic radiation and offer protection to biological beings and electronic data. Herein, we fabricated a novel HoFeO 3 @WSe 2 @SiO 2 composite via the co-precipitation method. The microwave absorption properties of the HoFeO 3 ,WSe 2 , SiO 2 and HoFeO 3 @WSe 2 @SiO 2 (with 25, 35 and 45 wt% loading) were examined in the X-band frequency range. 35 wt% filler loading shows reasonable reflection loss values with the broadest effective absorption bandwidth (EAB). The optimum impedance matching is responsible for the enhanced microwave absorption performance of the HoFeO 3 @WSe 2 @SiO 2 with 35 wt% filler loading. In addition, the best sample is measured using both waveguide and free-space techniques and the results have been compared. The free-space method has been demonstrated to be an effective alternative testing strategy due to its contact-free and non-destructive features. Furthermore, the technique described in this study to design innovative HoFeO 3 @WSe 2 @SiO 2 microwave absorbers can offer significant assistance with a wider absorption band. In this context, HoFeO 3 @WSe 2 @SiO 2 is expected to be used as a highly efficient microwave absorbent. [ABSTRACT FROM AUTHOR]

In this study, achieving NiCo 2 S 4 /AgBr composites is a step in the right direction toward developing efficient microwave absorption fillers. The rough-surfaced NiCo 2 S 4 /AgBr coupled micro-sphere offers a significant enhancement in complex permittivity by changing filler loadings, due to the Debye relaxation process and high conductivity. Moreover, as an efficient wave absorber, the optimal sample demonstrates a decent minimum reflection loss (RL mini) value of −17 dB and its qualifying absorption bandwidth (with RL < −10 dB) astonishingly encompasses the entire X-band (4 GHz). Additionally, the free-space technique was used to analyze the best sample, and the outcomes were compared. Touch-free and non-invasive nature of the free-space methodology has shown it to be a potentially viable testing method. So, comprehensive structural and compositional characterization, along with tunable properties and alternative testing method for preparing superior-quality NiCo 2 S 4 /AgBr samples, paves the way for exciting new microwave absorbents. Hence, NiCo 2 S 4 /AgBr is anticipated to be a very effective microwave absorber. [ABSTRACT FROM AUTHOR]

Advanced high-performance microwave absorber development now revolves around achieving better microwave absorption performance and intelligent electromagnetic property control. Effectively adjusting electromagnetic microwave dissipation qualities throughout a wide frequency range has been mostly unexplored, particularly for manufactured absorbers. Innovative and high-performance absorber materials are produced and analyzed in this study. Solvothermal preparation is used to synthesize polygonal-shaped CuCo 2 S 4 particles that are embellished with Cu 2 S particles. The permittivity and permeability of polygonal CuCo 2 S 4 particles decorated with Cu 2 S particles are significantly altered, which further affects the nanocomposite's performance in terms of microwave absorption. At a filler loading of 40 wt percent, the composite exhibits exceptional microwave absorption capabilities, and at a thin thickness of 1.5 mm, its effective absorption bandwidth (EAB) approaches 4.5 GHz, covering the whole X-band frequency range. The produced composite has outstanding dissipation qualities owing to the synergistic effects of numerous attenuation mechanisms and hetero-interfaces, where the ideal microwave dissipation strength is up to −32 dB. [ABSTRACT FROM AUTHOR]

Due to the widespread usage of electronic gadgets, electromagnetic interference and radiation pollution have become urgent problems. To reduce or eliminate electromagnetic pollution and interference, microwave absorption materials (MAMs) are urgently needed. Here, a solvothermal fabrication technique has been used to create a MoSe 2 structure that resembles a flower and a MnFe 2 O 4 @MnO 2 architecture that resembles a rod. To evaluate the properties of microwave absorption, single-layer and bilayer samples have been preapred with loading ratios of 15, 35 and 45 wt percent. When it comes to single-layer samples, a flower-shaped MoSe 2 structured sample with a 35-wt percent loading performs better in terms of microwave absorption. In bilayer absorbing samples, the top layer of the flower-like MoSe 2 structure exhibits high absorption capability. Moreover, samples with a higher loading ratio showed better absorption ability. Findings reveal that the primary reasons for the improvement in microwave absorption performance of bilayer samples are the layered structures are the higher electrical conductivity of Se in M o S e 2 , multiple reflections in the layered structure, and a higher polarization loss. Moreover, in bilayer samples, the thickness of both layers was regulated to tune the microwave absorption properties. The results of this study may be useful in developing advanced single layer and bilayer MAMs in the future. [ABSTRACT FROM AUTHOR]

The electromagnetic pollution problem, particularly at microwave frequencies, poses a threat to not only sensitive technological gadgets but also to the health of humans. Therefore, there is a great need for lightweight and highly effective microwave-absorbing materials (MAMs). Here, we fabricated a hierarchical flower-like MoSe 2 structure and a rod-like MnFe 2 O 4 @MnO 2 architecture via a solvothermal method. Single-layer and bilayer samples were fabricated to study the microwave absorption feature. In single-layer samples, the flower-like MoSe 2 structure has better microwave absorption properties than the rod-like MnFe 2 O 4 @MnO 2 architecture. And in bilayer absorbing samples, a sample with a flower-like MoSe 2 structure as the top layer shows high absorption performance. Moreover, in bilayer samples, changes were made to the thickness of both layers to find the best parameters. An optimal bilayer sample has been achieved with a flower-like dielectric MoSe 2 structure as a top layer having a 1 mm thickness and magnetic MnFe 2 O 4 @MnO 2 as a bottom layer also with a 1 mm thickness; indicating that a strong absorption can only be attained by balancing dielectric loss and magnetic loss. Moreover, the optimal sample shows decent absorption with an effective absorption bandwidth (EAB) of 5.4 GHz (14.7–9.3 GHz) with a 1 mm thickness of each layer. The simulated results of the optimal sample have also been compared with experimental results. These results suggest a different approach for developing MAMs in the future. [ABSTRACT FROM AUTHOR]

The concept of multilayers and filler content has been utilized as an effective technique to acquire excellent microwave absorption performance. MoS 2 @MXene nanocomposites have been successfully synthesized after exfoliation of the MXene and MoS 2 particles were embedded on its surface. MoS 2 @MXene achieved the minimum Reflection Loss (RL) of −51 dB with 30% ratio in wax. The involved mechanisms are discussed in detail including the synergetic effect between MXene and MoS 2 particles which improved the dielectric loss of the MoS 2 @MXene composites as a result of multiple reflections in the layered structure of MXene, abundant functional groups on the MXene surface and positive effect of the increase in surface area. Moreover, the radar cross-section reduction performance has also been confirmed by using simulation technology. The obtained MoS 2 @MXene composite proved as an excellent microwave absorbing material for future applications. [ABSTRACT FROM AUTHOR]

Bismuth based pyrochlores have attracted a massive interest in the modern research areas owing to their structural tenability and variety of physical properties. The structural variation and its consequent effects on dielectric relaxation have been presented in this work by synthesizing a series of La-mediated Bi 2-x La x Mg 2/3 Nb 4/3 O 7 (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) ceramics using sol–gel auto-combustion technique. Coexistence of fluorite and cubic pyrochlore phases in the parent composition and gradual enrichment of pyrochlore phase with increase of substitution contents was observed from the structural analysis. Distortion of spherical symmetry of grains with reduced grain size from 950 to 500 nm was revealed by field emission scanning electron microscope. The presence of required constituent elements with their correct proportion was analysed using energy dispersive X-ray spectroscopy. Complex impedance study and frequency dependent dielectric dispersion analysis was performed to check ac -conductivity and to explore potential of material for energy storage applications. With the help of complex modulus analysis, the range of carrier transportation inside the material was distinguished in different frequency regimes. [ABSTRACT FROM AUTHOR]

Electromagnetic absorbent materials have received significant attention, recently, due to the growing concern about microwave contamination caused by widespread electronic devices. So, a lot of work has been done to develop advanced absorbing materials with excellent performance. Here, B i 2 S 3 decorated L a C o O 3 nanocomposite has been fabricated via a solvothermal method. To study the microwave absorption properties, L a C o O 3 @ B i 2 S 3 nanocomposites with 5, 15, 25, 35 and 40 wt% loadings were prepared. With optimal microwave absorption performance, a 35 wt% sample has decent minimum reflection loss (RL mini) with qualified frequency bandwidth (RL > 10 dB) covering nearly the whole X-band. Enhancements in microwave absorption efficiency of 35 wt% sample are ascribed to the highest dielectric loss, highest magnetic loss, maximum attenuation constant, as well as optimal impedance matching value. Furthermore, the optimal sample is tested via two measurement techniques; waveguide and free-space methods. A Comparison has been drawn between the variation of reflection loss measured by both methods. The free-space approach proves a good alternative measurement technique with contact-free and non-destructive benefits. Our findings may be useful in the design and fabrication of L a C o O 3 @ B i 2 S 3 nanocomposites for efficient microwave absorbers. [ABSTRACT FROM AUTHOR]

A major challenge in the discovery of high-energy lithium-ion batteries (LIBs) is to control the voltage stability and Li+ kinetics in lithium-rich layered oxide (LrLO) cathode materials. Although these materials can provide a higher specific capacity compared to the current industrially used cathodes, the substantial voltage decay and low Li+ diffusion during long term cycling is a serious reason for hindering their practical applications. In order to suppress the voltage decay in lithium-rich cathode materials, herein we introduce the Ti doping into Li 1.2 Mn 0.56 Ni 0.17 Co 0.07 O 2 cathodes. Also, the influence of Ti doping on the crystalline internal structure, surface chemistry, cycling retention, and Li+ kinetics of Li 1.2 Mn 0.56 Ni 0.17 Co 0.07 O 2 cathodes have been focused in this work. The Ti doping effectively enhances the structural/interfacial stability of the cathode and accelerates the Li+ kinetics by expanding the lattice, thereby significantly realizing its voltage/cycling stability and high-rate capability. Experimental results show that Ti-doped LrLO (1% Ti) has achieved high electrochemical kinetics as the discharge cycle retention increased from 61.58% (pristine) to 80.0% after 180 cycles at 1 C, with 150.3 mAh g−1 showing superior high-rate performance at 5C. Ex-situ XRD results confirmed the better structural stability of Ti-doped LrLO after high-rate electrochemical cycling. Our findings provide a suitable element doping strategy for regulating the voltage decay and cycle retention of LrLO, thus promoting their real-world application in future batteries. [ABSTRACT FROM AUTHOR]

The nanosized mixed metal oxides (Ca 3 Co 2 O 6 , CaMnO 3 and Ca 2 CuO 3 ) have been synthesized and their electrochemical performance as supercapacitor electrodes have been evaluated. All of them show good pseudocapacitance in KOH electrolyte with specific capacitance of 563, 384 and 275 F g −1 for Ca 3 Co 2 O 6 , CaMnO 3 and Ca 2 CuO 3 , respectively. The charge kinetics of Ca 3 Co 2 O 6 is further evaluated by electrochemical impedance spectroscopy and the results show the low resistivity of Ca 3 Co 2 O 6 and its charge kinetic shows little variation after long continuous cycling. The present study signifies the successful application of nanosized mixed metal oxides as supercapacitor electrode. [ABSTRACT FROM AUTHOR]

Composition and structural design play a very influential role in the microwave absorption (MA) manipulation of ferrite/carbon composites. Here, by carefully choosing the dimensionality of the bio-carbon materials, the interfacial geometries and MA properties of ferrite/bio-carbon composites have been controlled effectively. The one dimensional (1D), two dimensional (2D), and three dimensional (3D) biomass-based carbon materials decorated with ZnFe 2 O 4 (ZFO) particles were obtained respectively from carbon fibers (1D), tree leaves (2D), wheat straw (2D), peanut shell (3D) and orange peel (3D) by a simple two-step synthesis method. With increasing the bio-carbon's dimensionality from 1D, 2D to 3D, the ferrite/carbon composite's MA properties are promoted and the minimum reflection loss is enhanced from −9 dB to −45 dB. By changing the ZFO/3D-bio-carbon samples' thickness, a broad absorption range from 4 to 18 GHz can be covered. Moreover, the effective absorption bandwidth for ZFO/3D-bio-carbon can be modified up to 7.1 GHz, which covers the whole Ku band. These observations identified the important roles of the ferrite/carbon interface and dimensionality of carbon materials and provided an effective and low-cost route to design microwave absorption materials based on biomass-industrial waste composites. [ABSTRACT FROM AUTHOR]