High-efficiency Electromagnetic Wave Absorption Research Articles

Magnetic media synergistic carbon fiber@Ni/NiO composites for high-efficiency electromagnetic wave absorption

Electromagnetic wave (EMW) absorbing materials have garnered significant attention for their potential applications in information security and military stealth fields. However, the development of highly efficient EMW absorbing materials possessing characteristics such as being “thin, lightweight, broadband and strong” remains a considerable challenge. Addressing this challenge involves the construction of low-dimensional composite material systems, which proves to be an effective approach. Carbon fiber (CF) is highly regarded for its light weight. In this study, we developed a simple and innovative sol–gel strategy to fabricate CF@Ni/NiO composites. The results demonstrate that the incorporation of Ni/NiO particles into CF materials substantially enhances the ferromagnetic properties of CF@Ni/NiO composites. An optimum reflection loss (RL) of CF@Ni/NiO-3 is −55.58 dB at 15.4 GHz with a corresponding thickness of merely 1.7 mm. An effective absorption bandwidth (EAB) reaches a maximum of 6.0 GHz at a thickness of 1.8 mm. Meanwhile, the radar cross section (RCS) reduction value at 6 GHz reaches 29.92 dB m2. The uniform distribution of Ni/NiO nanoparticles not only establishes a magnetic coupling network but also creates abundant heterogeneous interfaces with CF, thereby enhancing interfacial polarization. The successful fabrication of CF@Ni/NiO composites will facilitate the development and broad application of advanced electromagnetic wave (EMW) absorption materials in the aviation and aerospace sectors.

Multifunctional graphene/Ti3C2Tx MXene aerogel inlaid with Ni@TiO2 core-shell microspheres for high-efficiency electromagnetic wave absorption and thermal insulation

The demand for high-performance electromagnetic wave absorbing (EMA) materials featured with strong attenuation ability, extended absorption bandwidth and ultralight property is imperative yet remains challenging. Herein, a three-dimensional hierarchically porous reduced graphene oxide (rGO)/Ti3C2Tx MXene aerogel embedded with Ni@TiO2 core–shell microspheres was prepared via directional freeze-drying followed by a mild annealing process. The divergence in structure and multicomponent dielectric/magnetic features bring about optimized impedance matching characteristic, multiple polarization and loss pathways, collectively contributing to the excellent absorption performance. As a result, the Ni@TiO2/MXene/rGO (NTMRG-2) aerogel exhibits optimized EMA capability with a maximal effective absorption bandwidth (EABmax) of 6.48 GHz at a lower loading level of 5 wt% in the supporting matrix, covering the whole Ku band. Additionally, it achieves a minimum reflection loss (RLmin) of −71.4 dB with a matching thickness of 2.04 mm. Moreover, the aerogel also exhibits an ultra-light density of 5.58 mg cm−3, superior thermal insulation capacity (close to air) and hydrophobicity, underscoring its potential for multiple applications in various scenarios.

Bead-like Co/C@MoS2Composites connected by Multi-Walled carbon nanotubes for high-efficiency electromagnetic wave absorption

This study presents a novel approach to synthesize a composite material composed of bead-like Co/C nanoparticles anchored on MWCNTs, encapsulated by MoS2 nanosheets through a combination of carbonization and hydrothermal treatment using ZIF-67 as the precursor. The resulting composite demonstrates exceptional electromagnetic wave (EMW) absorption performance, with a minimum reflection loss (RL) of −63 dB at a thickness of 2.44 mm and an effective absorption bandwidth (EAB) of 7.2 GHz when RL is below 10 dB together with an expanded EAB of 12.3 GHz (d = 5 mm).The superior absorption capabilities arise from a well-thought-out design of material composition and structure. The synergy of Co/C and MWCNTs enhances ferromagnetic resonance, conductivity, and polarization loss, while sulfur vacancies in MoS2 act as polarization centers, facilitating dipole polarization and efficient conversion of electromagnetic wave energy. The core–shell structure and heterogeneous interfaces introduce various energy loss mechanisms, including multiple polarizations, scattering effects, and dielectric loss. This work introduces a facile method for synthesizing a composite material with outstanding EMW absorption performance. The synergistic combination of unique material components and the carefully engineered structure make this composite a promising candidate for advanced applications in electromagnetic wave absorption technology.

Hierarchically three-dimensional ZrO2/Fe3O4/C nanocomposites with Janus structure for high-efficiency electromagnetic wave absorption

Hierarchically three-dimensional (3D) materials present a pivotal challenge and opportunity in achieving effective microwave absorption with synergistic effects. In this work, α-Fe2O3@ZrO2 with core-shell structure were fabricated in-situ on aramid nanofibers by a solvothermal method. Following calcination, 3D ZrO2/Fe3O4/C nanocomposites with Janus structure have been successfully synthesized. By controlling the lattice match and mismatch in both processes, a core-shell structure of α-Fe2O3@ZrO2 and Janus structure of ZrO2/Fe3O4 have been well-define performed. The composite material ZrO2/Fe3O4/C-700 has a minimum reflection loss (RLmin) of −67.4 dB at a thickness of 2.0 mm. The effective absorption bandwidth (EAB) at a thickness of 2.4 mm is 6.0 GHz (11.0–17.0 GHz). This study provides a novel strategy for fabricating high-efficiency electromagnetic wave absorption materials with dual synergistic effects in nanosized scale.

Integrated design of MOFs-derived 0D/1D/2D/3D hierarchical network for high-efficiency electromagnetic wave absorption

To overcome electromagnetic pollution issues, multi-dimensional carbon-magnetic composites have gained attention. In this study, a 2D nanosheets stacked 3D network with 0D Co particles and 1D CNTs was synthesized via hydrothermal and annealing method. The nitrogen-doped porous 3D crosslinked network constructed with intertwined 1D and 2D components (CNTs, PDA-derived carbon, and MOFs-derived carbon) effectively extends the propagation pathway, providing superior conductive loss. Moreover, the 3D magnetic-electrical porous heterostructure greatly enhances the multiple scattering and reflection of the incident waves, as well as induces excellent eddy current loss. In addition, 0D Co nanoparticles exhibit multi-mode magnetic resonances and optimize impedance matching characteristics to capture more electromagnetic waves (EMWs). The microstructures, consisting of rich defects and multilevel heterogeneous interfaces, stimulate multidimensional advantages to regulate relaxation time for optimized dipolar polarization and interface polarization. Consequently, the multidimensional Co/CNTs@C heterostructure displays an optimum absorption of −59.1 dB at 11.3 GHz (loading of 10 wt%) and an ultra-width effective absorption band (EAB) of 8.1 GHz (20 wt%). Relevant simulation experiments demonstrate the strong absorption and extremely poor reflection, testifying its surprising performance. Overall, this work provides a novel strategy for preparing MOFs-derived multidimensional EMW absorbing materials.

High-efficiency electromagnetic wave absorption of lightweight Nb2O5/CNTs/polyimide with excellent thermal insulation and compression resistance integration

With the widespread application of electronic devices, multifunctional electromagnetic wave (EMW) absorbing materials suitable for complex high-temperature and high-pressure environments, have attracted tremendous research attention. Herein, multifunctional polyimide (PI) composites doped with fluffy Nb2O5/CNTs microspheres (NBCP) were prepared by combining the ultrasonic spraying process and freeze-drying technique. Introduction of fillers results in the formation of diverse conduction paths and heterogeneous interfaces, which enhance the dielectric loss. Furthermore, the multi-porous structure of the PI matrix induces multiple reflection scattering events and improves the impedance matching. Such a multi-loss mechanism endows NBCP with an excellent EMW absorption performance. At 15 vol% filling, the minimum reflection loss is −41.66 dB, the effective absorption bandwidth is 2.63 GHz, and the radar cross-section is reduced by 85%. Furthermore, NBCP exhibits outstanding mechanical properties and a thermal insulation of over 100 °C in thermal environment at 150 °C. The proposed multifunctional NBCP is thus an efficient EMW absorber that offers significant potential for applications in harsh environments.

Ni-based PCS-derived adsorbent with superior electromagnetic absorption capacity and reduced radar cross section

Low-cost and high-efficiency electromagnetic wave absorption materials had extremely broad application prospects in the realms of military and civilian domains. A series of Ni-based PCS-derived adsorbents made from precursor infiltration pyrolysis at different pyrolysis temperatures were investigated in this research. The results showed that after being pyrolyzed at 1200 °C, the Ni-based PCS-derived adsorbent possessed the lowest reflection loss value of −59.52 dB, while it reached a peak effective absorption bandwidth of 2.84 GHz with 1000 °C treatment, of which the calculated electromagnetic absorption efficiency was meanwhile the best. Besides, the simulation results showed that the adsorbent after being pyrolyzed at 1000 °C could minimize the radar cross section of the target, of which the strongest radar cross section reduction value was 21.34 dB·m2, significantly enhancing its stealth performance. Therefore, the Ni-based PCS-derived adsorbent possessed great electromagnetic wave absorption performances under conditions of high-temperature pyrolysis, which provided a reference for future electromagnetic wave absorption material design.

Watermelon pulp biochar decorated with Co3Fe7 for high-efficiency electromagnetic wave absorption

Bio-char decorated with inorganic magnetic component has shown great potential as a microwave absorbent because of the synergistic effect of two components. This composite holds promising prospects for applications in both military and civilian sectors. However, the composition and structure design of magnetic material/bio-char composites is still a challenge. Herein, the Co3Fe7/watermelon pulp biomass carbon (WPC) composite was designed. CoFe2O4 was converted into Co3Fe7 when co-calcined with pre-treated watermelon pulp (PWP). The EAB of Co3Fe7/WPC reaches 6.00 GHz at the thickness of 2 mm. The results show that this exceptional absorption performance of Co3Fe7/WPC is owed to its optimal impedance matching, multiple polarization and superior conductive loss. This work provides reference value for the preparation strategy of sustainable high-efficiency electromagnetic wave absorbing materials.

Structural engineering of rare earth metal-organic frameworks derivatives with high anisotropy for high-efficiency electromagnetic wave absorption

Structural engineering and component design are crucial for conceiving outstanding metal-organic frameworks (MOFs)-based electromagnetic wave (EMW) absorption materials. However, an efficient and direct clarification of the structural influences on the EMW absorption performance of MOF-based absorption materials remains highly challenging and still awaits exploration. To this end, we synthesized a new type of rare earth (RE) MOFs with hexagonal-bipyramidal, snowflake-like, and dendritic structures through facilely controlling the solvent ratios in a scalable coprecipitation approach. The MOF-derived CeO2/Co/C hybrids with the same component content inheriting the morphological structures showcased tunable dielectric property and EMW absorption performance. The dendritic MOF derivatives with the highest anisotropy achieved a superior EMW absorption performance, manifesting a minimum reflection loss value of −71.5 dB at 1.7 mm and an effective absorption bandwidth of 5.2 GHz at 1.6 mm thickness, comparable to those of the best EMW absorbers. This work not only confirmed the high potential of RE MOF derivatives for EMW absorption, but also directly and efficiently unveiled the mechanism of morphological structure on the dielectric property and EMW absorption performance for the MOF-based EMW absorption material.

CNTs-improved electromagnetic wave absorption performance of Sr-doped Fe3O4/CNTs nanocomposites and physical mechanism

Electromagnetic wave pollution is a serious environmental problem, and it is urgent to develop high-efficiency electromagnetic wave absorption (EMA) materials. In this paper, carbon nanotubes (CNTs) were combined with Sr-doped Fe3O4 nanoparticles to form Sr-doped Fe3O4/CNTs nanocomposites with by hydrothermal method. After the characterization of microstructure and magnetic properties, EMA properties of Sr-doped Fe3O4/CNTs nanocomposites are investigated in detail. The well-dispersed CNTs lead to the uneven average grain size of Sr-doped Fe3O4 nanoparticles and a little decrease of saturation magnetization. While CNTs greatly improve EMA performance, and SFC1 sample exhibits the minimum reflection loss value of −65.64 dB at 6.32 GHz with the thickness of 3 mm. CNTs reduces the natural resonance of magnetic loss while increasing the permittivity, conductivity, and heterogeneous interfaces. As the result, Sr-doped Fe3O4/CNTs nanocomposites exhibit not only better impedance matching but also higher electric dipole polarization relaxation loss, interfacial relaxation loss, conductivity loss, and eddy current loss. In this way, the excellent EMA performance is attributed to the good impedance matching, intense dielectric loss and enhanced eddy current loss for Sr-doped Fe3O4/CNTs nanocomposites.

Bayberry-like bimetallic CoNi-MOF-74 derivatives/MXene hybrids with abundant heterointerfaces toward high-efficiency electromagnetic wave absorption

The flourishing development of electronic devices and radar detection technologies necessitates the urgent creation of high-efficiency electromagnetic wave (EMW) absorption materials with expansive absorption bandwidths. Although MXene has garnered significant interest in the domain of EMW absorption due to its tunable dielectric properties and structural designability, its high permittivity often results in poor impedance matching and a single loss mechanism, which makes it difficult to realize optimal EMW absorption capabilities. In this work, CoNi bimetallic metal–organic frameworks (MOFs) derived bayberry-like magnetic porous carbon (CoNiMPC)@carbon nanotubes (CNTs)/MXene (CNCM) hybrids were initially synthesized via simple solution precipitation, thermal treatment, and electrostatic self-assembly strategy. As anticipated, excellent EMW absorption characteristics were achieved by adjusting the ratio of CoNiMPC@CNTs and MXene. Multi-heterointerfaces consisting of zero-dimensional porous carbon, one-dimensional carbon nanotubes, and two-dimensional (2D) MXene, electrical/magnetic coupling effects, and polarization loss induced by abundant heterointerfaces endow the prepared CNCM hybrids with high-performance EMW absorption. Notably, the CNCM-7 hybrid material exhibits a minimum reflection loss (RLmin) of − 65.3 dB at 6.8 GHz with a mere 2.7 mm thickness and an effective absorption bandwidth (EAB, RL < −10 dB) of 5.0 GHz at a thickness of 1.27 mm. This study proposes a unique viewpoint and approach towards the design and preparing high-performance MXene-based EMW absorption materials.

α-PW11Fe(Co/Ni)/BC derived carbon fiber based nanocomposites for high efficiency electromagnetic wave absorption via synergistic effects of polarization and conductance

In order to enhance the wave-absorbing performance of dielectric/carbon fiber based wave-absorbing materials and explore the dissipative mechanism of electromagnetic wave (EMW), this study utilizes liquid diffusion of K4PW11O39Fe(III)(H2O) (α-PW11Fe), K5PW11O39Co(II)(H2O) (α-PW11Co), K5PW11O39Ni(II)(H2O) (α-PW11Ni) and bacterial cellulose (BC), as well as high temperature carbonization strategy to prepare polycrystalline polyphase transition metals and their compounds with three dimensional porous conductive network structure loaded carbon fiber based nanocomposites wave-absorbing materials. By changing the element type, drying mode and filling amount, we can achieve the tunability of electromagnetic parameters and absorbing properties. Impressively, the best synthesized sample 20 %-α-PW11Ni/BC derived carbon fiber based nanocomposites has excellent EMW absorption properties, with a maximum reflection loss (RL) of -68.1 dB at 2.6 mm matching thickness. The effective absorbing bandwidth (EAB) is 7.2 GHz, and the RL less than -10 dB in the frequency band of 2.2–5.0 mm thickness is 5.3 to 18.0 GHz. The excellent absorbing performance is attributed to the synergy of polarization and conductance, balanced impedance matching, good interface/dipole polarization, and multiple reflections and scattering. Therefore, the prepared composite has a broad application prospect in the field of EMW absorption, and provides a new idea for the design of new efficient absorbing materials.

Straw-bundle-like rare earth metal-organic frameworks derivatives for high-efficiency electromagnetic wave absorption

Metal-organic frameworks (MOFs) derivatives have been widely developed as electromagnetic wave (EMW) absorption materials. Nevertheless, owing to the diverse metal ions, organic ligands, and crystal morphologies of MOFs precursors, challenges still remain to overcome towards directly ascertaining the contribution of metal components on EMW absorption for precisely designing high EMW absorption performance of MOF derivatives. Here, we synthesize a series of rare earth (RE) MOF derivatives via a facile, scalable coprecipitation followed by carbonization approach. Thanks to the similar chemical property derived from lanthanide shrinkage of RE elements, the MOF-derived RE oxides (REO)/carbon (REO = CeO2, La2O3, Nd2O3) hybrids exhibit the identical straw-bundle-like microstructure, efficiently assisting the elucidation of the roles of metal components in promoting EMW absorption. Benefiting from the tunable bandgap of various REO as well as carbonization temperature, the 800 °C-carbonized CeO2/carbon shows a minimum reflection loss of − 58.7 dB at a thickness of 1.7 mm and an effective absorption bandwidth of 5.0 GHz, comparable to the best EMW absorbers. This work not only demonstrates novel, high-performance RE-MOF derivatives, but also offers a general yet efficient strategy for designing metal components to achieve high-efficiency MOF-based EMW absorbers.

Hollow silicon carbide microspheres for excellent and lightweight electromagnetic wave absorber

Developing semiconductor ceramic materials with lightweight, outstanding stability, and high-performance electromagnetic wave (EMW) absorption are attractive for harsh environments. Due to thermal and chemical stability, designable microstructure, and tunable dielectric property, microstructured silicon carbide (SiC) ceramics offer promising potential as excellent EMW absorbers while limited by the scarce fabricating methods. Here, a simple coaxial electrospinning technology and the high-temperature calcination process are developed for the first time to fabricate hollow SiC microspheres (HSCMs) for EMW absorbers. Owing to the sizeable SiC-free space interface in the shell and internal void, the inner hollow structure also endows HSCMs with excellent EMW absorbing properties. By comparing with the composite of 40 wt% solid SiC microspheres (SSCMs)/paraffine, it is found that the 40 wt% HSCMs/paraffin composite exhibits superior dielectric properties and a minimum reflection loss (RL) value of − 61.6 dB at 7.7 GHz and 3.4 mm thickness, associated with the most considerable adequate absorption bandwidth of 4.9 GHz (from 12.6 to 17.5 GHz) at 1.9 mm thickness. This work gives rise to a handy method for fabricating hollow SiC with lightweight and high-efficiency EMW absorption. It will potentially boost the development of next-generation EMW absorbers for harsh environment applications.

Facile fabrication of biomass chitosan-derived magnetic carbon aerogels as multifunctional and high-efficiency electromagnetic wave absorption materials

Biomass chitosan-derived porous carbon-based materials take the advantage of light weight, adjustable intrinsic conductivity, and environmental friendliness, attracting more attention in the field of electromagnetic compatibility. However, exploring a facile fabrication method to achieve rational structure design and electrical-magnetic coupling for electromagnetic absorption performance enhancement still remains challenging. Here, a unique honeycomb-like porous cobalt/carbon aerogel is fabricated through the directional freezing-drying and carbonization process, and abundant and even-distributed cobalt particles in-situ grow on the carbon skeletons. The aerogel exhibits an impressive electromagnetic wave absorption performance of a −75.8-dB absorption intensity and a −256.9-dB mm−1 specific reflection loss at a low filling content (10%), as well as an 8.53-GHz effective absorption bandwidth. Besides, the aerogel also demonstrates classy radar stealth and thermal insulation performance. The eco-friendly, easily fabricated, and high-performance cobalt/carbon aerogel suggests broad application prospects for electromagnetic compatibility and protection, thermal management, and multifarious electron devices.

Synthesis of high-entropy MXenes with high-efficiency electromagnetic wave absorption

Synthesis of high-entropy MXenes with high-efficiency electromagnetic wave absorption

1D CNTs assembled MOF-derived hollow CoSe2@N-doped carbon constructed high-efficiency electromagnetic wave absorbers

Optimizing impedance matching is crucial to achieve high-efficiency electromagnetic wave (EMW) absorption performance. In this work, Hollow CoSe2@N-doped Carbon/Carbon Nanotube-x (HCSC/CNTs-x) with unique three-dimensional conduction network was synthesized by using protection etching and high-temperature selenization strategies. The conductivity of HCSC/CNTs-x was regulated by varying the content of CNTs, and the extended three-dimensional electron transport pathway resulted in enhanced conduction and multiple reflection loss, while also optimizing impedance matching. Hollow CoSe2@N-doped carbon (HCSC) further facilitates the optimization of impedance matching. The abundant heterogeneous interfaces and defects induce strong interface polarization and dipole polarization, and the multiple loss mechanisms work in concert to confer excellent EMW absorption performance to HCSC/CNTs-x. The RLmin of HCSC/CNTs-30 reaches −41.68 dB, and the EABmax is 4.92 GHz at only 2.0 mm. The design strategy of three-dimensional conduction network of HCSC/CNTs-x provides an effective way to achieve the impedance matching optimization of CoSe2-based EMW absorption materials.

Hollow porous magnetic/magnetic heterostructured CoFe/defective spinel microspheres template-free synthesis and effective modulation of microwave absorption performance

To create a spinel ferrite with excellent performance for electromagnetic (EM) wave absorption in the low frequency range of 4–6 GHz, compositions based on Co0.75Zn0.125Fe0.125Fe2O4 (CZF–1) and Co0.5Zn0.25Fe0.25Fe2O4 (CZF–2) with multiple elements substituted for A sites were synthesized by using solvothermal method. Hollow porous magnetic/magnetic heterostructure microspheres (HHMs) of CZF–A1 and CZF–A2 with multiple interfaces were prepared by hydrogen–thermal reduction of CZF–1 and CZF–2, and their unique structure and EM absorption properties were investigated in detail. The widest effective absorption bandwidth (EAB) of CZF–A1 and CZF–A2 was 4.1 GHz (13.6–17.7 GHz) and 3.7 GHz (8.0–11.7 GHz) for a corresponding thickness of 1.4 mm and 2.0 mm, respectively. In addition, the minimum reflection loss (R.Lmin) of CZF–A1 and CZF–A2 reached –49.1 dB (at fm = 13.4 GHz) and –45.0 dB (at fm = 4.2 GHz) at a thicknesses of 1.6 mm and 3.7 mm, respectively. More specifically, in the low frequency region of 4–6 GHz, CZF–A1 and CZF–A2 exhibited excellent EM wave absorption due to the effective regulation of their natural resonance frequency. The EM wave absorption frequency band of CZF–A1 and CZF–A2 samples was able to completely cover the 4–6 GHz frequency region for at coating thickness of CZF–A1 and CZF–A2 was only 3.5 mm and 3.3 mm respectively, and their R.Lmin reached –36.5 dB and –22.6 dB. Moreover, the absorption mechanisms of CZF–A1 and CZF–A2 including magnetic resonance, eddy current loss, interfacial polarization and dipole polarization were also investigated in detail. This research provides new insights and guidance for the development of spinel ferrite-based EM absorbers for high efficiency EM wave absorption in the low frequency (4–6 GHz) region.

Preparation and characterization of bifunctional wolfsbane-like magnetic Fe3O4 nanoparticles-decorated lignin-based carbon nanofibers composites for electromagnetic wave absorption and electrochemical energy storage

Recently, with the pursuit of high-efficiency electromagnetic wave absorption (EMWA) and electrochemical energy storage (EES) materials, multifunctional lignin-based composites have attracted significant interest due to their low cost, vast availability, and sustainability. In this work, lignin-based carbon nanofibers (LCNFs) was first prepared by electrospinning, pre-oxidation and carbonization processes. Then, different content of magnetic Fe3O4 nanoparticles were deposited on the surface of LCNFs via the facile hydrothermal way to produce a series of bifunctional wolfsbane-like LCNFs/Fe3O4 composites. Among them, the synthesized optimal sample (using 12 mmol of FeCl3·6H2O named as LCNFs/Fe3O4–2) displayed excellent EMWA ability. When the minimum reflection loss (RL) value achieved −44.98 dB at 6.01 GHz with an thickness of 1.5 mm, and the effective absorption bandwidth (EAB) was up to 4.19 GHz ranging from 5.10 to 7.21 GHz. For supercapacitor electrode, the highest specific capacitance of LCNFs/Fe3O4–2 reached 538.7 F/g at the current density of 1 A/g, and the capacitance retention remained at 80.3 %. Moreover, an electric double layer capacitor of LCNFs/Fe3O4–2//LCNFs/Fe3O4–2 also showed a remarkable power density of 7755.29 W/kg, outstanding energy density of 36.62 Wh/kg and high cycle stability (96.89 % after 5000 cycles). In short, the construction of this multifunctional lignin-based composites has potential applications in electromagnetic wave (EMW) absorbers and supercapacitor electrodes.

Hollow Co0.85Se@MoSe2 with Core–Sheath Structures Derived from Co Microchains for High Efficiency Electromagnetic Wave Absorption

Hollow and hierarchical structures are the desirable features for high-performance electromagnetic wave absorbing (EWA) materials. In this study, Co microchains were used as a matrix and a layer of MoSe2 nanosheets and nanospheres was loaded onto their surface through a one-step hydrothermal reaction. During this process, Co cations migrated from the inside to the outside of the nanowire and combined with Se anions to form hollow Co0.85Se microchains and the MoSe2 on the surface contributed to a hierarchical structure. The prepared Co0.85Se@MoSe2 composites showed dielectric and magnetic losses simultaneously, achieving a minimum reflection loss (RLmin) of −42.6 dB and an effective absorbing bandwidth (EAB) of 10 GHz (6.8–10.6 and 11.8–18 GHz) at the thickness of 2.3 mm. Co0.85Se@MoSe2 microchains were successfully synthesized for the first time using a cost-effective and simple solvothermal reaction. This work sheds light on the large-scale synthesis of Co-based microchains as well as a promising EWA material with a specific structure and multiple loss modes.