Microwave Absorption Capacity Research Articles

Construction of three-dimensional mesh porous Mo2C/carbon composites by chitosan salting-out for efficient microwave absorption

Constructing conductive network and adjusting impedance matching are effective ways to enhance the microwave absorption capacity of absorbers. However, the experimental procedures for preparing three-dimensional porous network are complex and often involve the use of hazardous agents. We proposed a simple and safe strategy to prepare porous three-dimensional network Mo2C/C composites. The salting-out method can change the aggregation state of chitosan macromolecules and make the free chitosan molecules form a porous three-dimensional network structure autonomously. In addition, the plus-charged amino on chitosan is able to attract minus-charged molybdate ions, which makes the surface of the 3D structured chitosan precursor covered with molybdenum-containing species. The result shows that the porous mesh structure and the heterogeneous interfaces combine to achieve excellent absorption performance of Mo2C/C with effective absorption bandwidth of 5.04 GHz at 1.8 mm. This work demonstrates that salting-out method broadens the idea of porous three-dimensional network electromagnetic wave absorbing materials.

Experimental and analytical study on heating and road performance of asphalt mixture with silicon carbide and ferroferric oxide composite structure layer

Microwave heating is currently considered to be the most promising clean energy technology for asphalt pavement deicing. In order to improve the heating efficiency of pavement surface, a 10 mm silicon carbide (SiC) and ferroferric oxide (Fe3O4) composite structure layer (CSL) was designed on the pavement surface. The surface heating efficiency and road performance of asphalt mixture with CSL were investigated by laboratory experiments, and the distribution of electromagnetic and temperature fields were analyzed by numerical simulations. The experimental results show that the surface temperature of asphalt mixture with CSL was 1.64 and 1.36 times higher than that of the ordinary asphalt mixture and the asphalt mixture with SiC and Fe3O4 composite material, and it remained stable before and after repeated heating and water bath, with a difference of only 1 ℃∼1.7 ℃. The asphalt mixture with CSL had good road performance. The Marshall stability, residual stability and interlayer shear strength could remain above 10 kN, 92% and 4 MPa after repeated heating. The numerical simulation results show that the asphalt mixture mixed with microwave absorbing materials produced a larger electromagnetic field intensity. The heat of asphalt mixture with CSL was mainly concentrated on the road surface because the absorbing material was concentrated on the road surface. In contrast, because there was no difference in microwave absorption capacity throughout the asphalt mixture with SiC and Fe3O4 composite material, the heat distribution was mainly influenced by the electromagnetic field intensity. In general, asphalt mixture with CSL has higher surface heating efficiency and road performance.

Asphalt mixture with nucleus-shell structural microwave enhanced aggregate: Structure design, preparation and performance

The natural aggregates in asphalt mixture with poor electromagnetic loss have poorer microwave absorption capacity and lower microwave energy utilization. The nucleus-shell structural microwave enhanced aggregate (NSSA) consisting with external microwave absorbing and heat collecting structure layer (ESL) and internal limestone was designed to enhance the microwave absorption capacity. The composition and thickness of the ESL were determined. The microwave heating efficiency, microwave energy utilization rate and water stability of asphalt mixture with NSSA and the influence of NSSA on the distribution of electromagnetic field intensity were studied by laboratory test and numerical simulation. The electromagnetic parameters test results show that the ESL had better impedance matching with air when the SiC: Fe3O4: cement: water = 1:2:15:6.3. The ESL thickness should not exceed 4.68 mm considering the penetration ability of 2.45 GHz electromagnetic wave. The microwave heating test results show that the heating rate and energy utilization rate of NSSA were 1.76 times and 5.93 times higher than those of limestone. Furthermore, the asphalt mixture with NSSA had higher heating rate, temperature uniformity and energy utilization rate. The overall water stability of asphalt mixture with NSSA remained the same or even better because the ESL wrapped the pores inside the limestone. The simulation results show that the asphalt mixture with NSSA had larger electromagnetic field intensity and better uniformity of electromagnetic field distribution during microwave heating. In conclusion, the NSSA and the asphalt mixture with NSSA has better microwave absorption capacity and microwave energy utilization rate.

NiFe2O4/coal-based carbon composites with magnetic properties and microwave absorption capacity prepared through microwave radiation and hydrothermal reaction

Nickel ferrite/coal-based carbon (NiFe2O4/CBC) composites were synthesized by using microwave irradiation and simple hydrothermal method. The effects of reaction conditions on particle size, morphology, magnetic, and microwave absorption properties of the NiFe2O4/CBC composites were systematically studied. In all NiFe2O4/CBC composites, NiFe2O4 microspheres with different shapes and sizes were anchored on the surface of CBC. By adjusting size of the NiFe2O4 particles, dielectric and magnetic properties of the NiFe2O4/CBC composites could be optimized simultaneously. For the NiFe2O4/CBC sample with the average particle size of NiFe2O4 to be 4.69 nm, when the thickness was 4.42 mm, the minimum reflection loss (RLmin) could reach − 63.15 dB at 9.89 GHz. Meanwhile, the maximum effective absorption bandwidth (EABmax) was 4.91 GHz (6.31–11.22 GHz) at a thickness of 5 mm, which almost covered the whole X-band. The s-shaped hysteresis loop of the sample revealed that it had typical superparamagnetic characteristics. The possible mechanism of microwave absorption was also discussed. Our NiFe2O4/CBC composites could be used as a new and efficient microwave absorption material.

Robust and thermostable C/SiOC composite aerogel for efficient microwave absorption, thermal insulation and flame retardancy

Carbon aerogel (CA) has been generally regarded as a potential electromagnetic wave (EMW) absorber, but unsatisfactory microwave absorption, mechanical and anti-oxidation properties are still the primary challenges for its application. Herein, a novel C/SiOC composite aerogel (CSA) was successfully synthesized by a simple copolymerization of dual sols, ambient pressure drying and thermal treatment process for the first time. The morphology and performance of the as-prepared CSA could be tailored just by controlling the initial ratio of silane and phenolic resin (PR) to adjust the content of SiOC in CSA, whose density was in the range of 0.252 to 0.294 g·cm−3 with a low thermal conductivity from 0.061 to 0.067 W·m−1·K−1. Notably, the EMW absorption capacity of CSA was greatly enhanced with the increase of SiOC content, with the optimal reflection loss (RL) value of −67.85 dB and effective absorption bandwidth (EAB) of 6.88 GHz, which was dramatically improved than CA (–22.89 dB, 5.34 GHz) and mainly ascribed to the optimized impedance matching characteristics and strong attenuation capacity. Meanwhile, compared with CA (2.63 MPa) with a density of 0.248 g·cm−3, the mechanical properties of CSA (3.30–5.12 MPa) were also remarkably improved, and the maximum compression strength was nearly doubled. Furthermore, CSA obtained superior oxidation resistance than CA and exhibited excellent flame-retardant properties. All the results indicated that CSA could be considered as a highly promising candidate for applications in extreme environments due to its lightweight, high strength and outstanding microwave absorption capacity along with good oxidation resistance, superior thermal insulation performance and high flame retardancy.

Effect of strong dielectric substances on the damage characteristics of rocks exposed to microwave radiation: Insight from experiments and mechanisms

It has been demonstrated that microwave pretreatment can weaken rocks, reduce tool wear, and improve mechanical rock breaking efficiency. The dielectric properties of rock minerals are a major factor affecting the ability of rocks to absorb microwaves, so it is important to conduct experimental research on rock modification to improve the microwave absorption capacity of rocks. The concept of “microwave-assisted absorbing reagents” has been proposed to increase the microwave absorption capacity of rocks. Sandstone specimens are first pretreated with strong dielectric substances before being exposed to microwave radiation to increase their microwave absorption capacity, then they are exposed to microwave fields and finally conducted to uniaxial compression tests. Enhancement in microwave absorption capacity of sandstone specimens is showed by P-wave velocity, nuclear magnetic resonance, and mechanical tests before and after microwave treatment. The results showed that barium titanate suspension and water are both effective microwave-assisted absorbing agents. The specimens treated with barium titanate suspension exhibited better microwave absorption capacity; in 5 kW microwave power irradiation, its p-wave velocity falls by 14.04%, porosity rises by 25.43%, and uniaxial compressive strength falls by 24.98%. Additionally, the failure form of sandstone specimens changes from brittle to plastic once it has fully absorbed microwave energy.

Enhanced Induction Heating and Self-Healing Properties of Steel Slag Powder Based Asphalt and Asphalt Mixture under Microwave Irradiation.

This paper aims to study the application feasibility of steel slag powder (SSP) in replacing limestone powder (LP) to enhance the heat release and self-healing properties of asphalt and an asphalt mixture. First, the microwave-heating characteristics of SSP and LP asphalt mortar were analyzed, and the differences in the microstructure and chemical composition between SSP and LP were compared. Secondly, through the DSR frequency sweep test, the optimal healing temperature of the two asphalt mortars was determined. Finally, asphalt mixtures with different SSP contents were prepared by replacing part of LP in the mixture in a gradation with SSP. Under microwave radiation, the temperature distribution of the mixture was explored, and the self-healing properties and factors affecting the healing were analyzed. Results demonstrated that there are metal oxides with high electromagnetic parameters such as Fe2O3 and CaO in SSP, therefore, asphalt and a mixture containing SSP were seen to have excellent microwave absorption capacity. The healing temperature of the two kinds of asphalt mortar was between ~50 °C and 60 °C. Under microwave radiation, the temperature of the asphalt mixture increased with the increase in SSP content, and the temperature difference decreased with the increase in SSP content. Asphalt mixtures with an LP content of 30%, 40%, 50%, 60%, and 70% replaced by SSP increased the healing index by 8.7%, 17.3%, 22.1%, 26.9%, and 27.7% compared with conventional asphalt mixtures. Temperature is the most important factor affecting the healing behavior of the asphalt mixture. With the increase in the damage times of the asphalt mixture, the overall healing index of the asphalt mixture showed a downward trend. However, the healing index of an asphalt mixture containing SSP can still be maintained at more than 50% after repeated mechanical damage.

Effect of nonequivalent doping on dielectric and microwave absorbing properties of LaFeO3-based ceramics

Development of microwave absorption materials (MAMs) with thin thickness, high oxidation resistance and tunable effective absorbing bandwidth (EAB) is particularly urgent for practical applications but remains a great challenge. In this work, a series of novel MAMs, (La1-xSrx)FeO3/Al2O3 pseudo-binary composites were synthesized, and their electromagnetic parameters, microwave absorbing capacity and related mechanisms were revealed systematically. Attributed to appropriate attenuation coefficients and superior impedance matching, the equilibrium phase in (La0.3Sr0.7)FeO3/Al2O3 pseudo-binary composite presents the best electromagnetic wave absorption property, in which RLmin = −38dB, effective absorption bandwidth (EAB: RL＜-10 dB) is up to 2.78 GHz with a thickness of 1.5 mm and its tunable EAB is 13.22 GHz when thickness ranged from 1 mm to 3 mm, indicating its is a superior MAM. The excellent microwave absorbing properties of (La0.3Sr0.7)FeO3/Al2O3 pseudo-binary composite is derived from space charge polarization caused by plenty of heterogeneous interfaces, dipole polarization introduced by doping, and conductive loss originating from directional movement of charge carriers.

One-Pot Synthesis of Ag/AgCl Heterojunction Nanoparticles on Polyaniline Nanocone Arrays on Graphene Oxide for Microwave Absorption

Heterointerfaces in microwave absorption materials can induce dielectric polarization relaxation for superior microwave absorption capacity. Nevertheless, the construction of favorable hierarchical structures in dielectric heterogeneous materials remains a considerable challenge. Herein, Ag/AgCl heterojunction (HAg) nanoparticles are successfully decorated on polyaniline (PANI)/graphene oxide (GO) sheets through simple one-pot interfacial polymerization. The synthesized HAg/PANI/GO hybrid exhibits superior microwave absorption performance due to the multi-heterogeneous and hierarchical structures, which provides numerous interface polarizations, dipolar relaxations, and improved impedance matching. The minimum reflection loss of the optimum HAg/PANI/GO hybrid reaches −61.14 dB at 11.32 GHz with an effective absorption bandwidth of 4.77 GHz in the range from 9.70 to 14.47 GHz. This work provides ideas for producing multi-heterogeneous and hierarchical structures to reach a high microwave absorption performance.

Syngas generation from different types of sewage sludge using microwave-assisted pyrolysis with silicon carbide as the absorbent

In this study, the pyrolysis of sewage sludge was explored through microwave-assisted pyrolysis. Three kinds of sludge (primary sludge, waste-activated sludge, and digested sludge) from a sewage treatment process were used. All three kinds of sewage sludge had a low microwave absorption capacity; therefore, an absorber was added to enable microwave-assisted pyrolysis. By using silicon carbide as the heating element, it was possible to increase the temperature within a short time by applying microwaves. During the microwave-assisted pyrolysis of sewage sludges, the amount of gas generated and the H2 and CO fraction of the produced gas increased as temperature increased. The pyrolysis of waste-activated sludge produced the greatest quantity of gas. However, the primary sludge produced the highest amount of syngas in terms of H2 and CO, which indicate the high-quality of the syngas.

Low infrared emissivity composite materials for multi-band camouflage

Infrared camouflage textile materials have the advantages of softness, portability, and wearability. They are the main raw materials of infrared camouflage clothing, backpacks, camouflage nets, and tents. In this paper, from the perspective of reducing infrared emissivity to achieve the purpose of camouflage, metal materials were selected as functional particles and combined with textile materials to prepare polyurethane infrared camouflage composite materials with low emissivity, whose lowest emissivity in the wavelength range of 2–22 μm can reach 0.58. On this basis, two kinds of low infrared emissivity composite materials that can be used for multi-band camouflage were developed. One is to add modified graphene into the coating to improve the conductivity of the coating and reduce the gloss of the coating, to prepare visible and infrared camouflage coated fabric. When the amount of graphene is 10% of the filler content, the coated fabric has low gloss and low emissivity at the same time. Compared with the fabric without graphene coating, the glossiness is reduced by 31%, while the infrared emissivity is only increased by 0.1. The second is to prepare composite materials with infrared camouflage and microwave absorption functions by compounding low infrared emissivity and microwave absorbing coating. The minimum infrared emissivity of the two composites was 0.76 and 0.58, respectively. In this study, a variety of materials was used to prepare low infrared emissivity fabrics with low glossiness or good microwave absorption capacity, which provided a reference for the preparation of multi-band camouflage fabrics and was expected to be applied in the field of military camouflage.

Enhanced microwave absorption capacity of iron-based catalysts by introducing Co and Ni for microwave pyrolysis of waste COVID-19 Masks

Inexpensive iron-based catalysts are the most promising catalysts for microwave-assisted deconstruction of waste plastics. However, the microwave heating efficiency of most of the synthesized iron-based catalysts is very low, in particular, the FeAl catalyst was prepared by microwave combustion method, and its mixture with disposable medical masks (DMMs) was only heated to about 150℃ within 10 min. Here, we introduce the second-phase metals (Co or Ni) into the FeAl catalyst, resulting in the rearrangement of the catalyst structure and electrons to give the catalyst good microwave absorption ability. The mixture of the catalyst and DMMs can be quickly heated to above 900℃ in 10 min, especially after reaching the melting point of plastic, the instantaneous heating rate reaches 350 ℃·min−1. under the unique microwave hot-spot pyrolysis mechanism, DMMs can be rapidly pyrolyzed into carbon nanotubes (19.65 wt%) and gas (77.65 wt%) within 14 min due to the efficient dehydrogenation efficiency and activity of Co. The corresponding H2 yield is up to 38.66 mmolH2·g−1DMMs, and the percentage of CO and H2 in the gas is as high as 90 wt%. This work improves the microwave conversion efficiency of iron-based catalysts by introducing second phase metals, and waste DMMs were efficiently converted into CO, H2 and CNTs, which can also be extended to other polymer or biomass chemical cycles.

A Study on the Heating and Deicing Performance of Microwave-Absorbing Asphalt Mixtures.

Road icing in winter brings challenges to traffic safety, and microwave heating and deicing technology is an effective method with the advantages of high efficiency and environmental protection. Magnetite has been widely used as a microwave-absorbing material in pavement. In this paper, magnetite powder formed by crushing natural magnetite and high-purity Fe3O4 powder after purification were mixed to replace mineral powder, and the magnetite aggregate was used to replace the limestone aggregate with the same particle size to enhance the asphalt mixtures' microwave absorption capacity. The effect of microwave heating time and microwave power on the heating of the asphalt mixtures was studied, and the heating performance of different thicknesses of the asphalt mixtures under microwave radiation was evaluated. The heating performance of the mixtures under different initial temperatures and ice layer thicknesses was also assessed. The results showed that the addition of the magnetite powder-Fe3O4 powder and the magnetite aggregate significantly enhanced the heating performance of the asphalt mixtures by microwave heating. The replacement of the magnetite powder-Fe3O4 powder, the microwave heating time, and the microwave power had positive effects on the heating efficiency of the asphalt mixtures. Moreover, the thinner asphalt mixtures had a better heating performance. The heating and deicing performance of the mixtures decreased with a decline in initial temperature. As the ice thickness increased, the deicing time of the specimen surface to reach 0 °C also increased.

Preparation of microcrystalline graphite/zinc ferrite composites with enhanced and tunable electromagnetic wave absorption using a high-temperature ball milling method

Microcrystalline graphite (MG)/zinc ferrite (ZFO) composites were prepared by a high-temperature ball milling method. The magnetic and microwave absorption properties of MG/ZFO composites were analyzed in the frequency range of 2.0–18.0 GHz. The results showed that MG has a favorable impact on the microwave absorption capacity of ZFO. The composites containing 10 wt% MG had a minimum reflection loss of −62.90 dB, which is almost a factor of 12 higher than for pure ZFO, and their effective absorption bandwidth (EAB, RL<−10 dB) covers frequency range of 5.84–7.92 GHz for a matching thickness of 3.9 mm, and for a matching thickness of 1.8 mm, the EAB covers frequency range of 12.87–17.70 GHz. A probable mechanism of microwave absorption for MG/ZFO composites is based on a synergistic combination of dielectric and magnetic losses. The attractive properties of prepared composites indicate that they are promising and competitive materials for use in microwave absorption.

Conversion of Polystyrene Plastic into Aviation Fuel through Microwave-Assisted Pyrolysis as Affected by Iron-Based Microwave Absorbents

As recycling plastics through microwave-assisted pyrolysis becomes gradually popular, the selection of microwave absorbents is therefore of great importance because plastics generally have low microwave absorption capacities, and microwave absorbents are then required to improve the heating and pyrolysis processes. In this study, conversion of polystyrene plastic into aviation fuel through microwave-assisted pyrolysis as affected by iron-based microwave absorbents (Fe, Fe3O4, and FeS2) was studied and reported for the first time. The heating performance, product yields, oil higher heating values, and aviation oil compositions with different microwave absorbents, microwave powers, and microwave absorbent loads were detailed. The results showed that Fe3O4 exhibited the highest average heating rate of 119.23 °C/min, and Fe had good selectivity for cycloalkenes, while FeS2 had good selectivity for olefins. The highest oil yield (97.67 wt %) was obtained at a pyrolysis temperature of 460 °C, microwave power of 650 W, and Fe load of 90 g, and the oil compositions were mainly monocyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons, olefins, and cycloalkenes with abundant C8–C16 hydrocarbons of 52.041–77.880 area%. The results indicated that polystyrene can be well converted into aviation fuel through microwave-assisted pyrolysis by screening the iron-based microwave absorbents.

Influence of SiC on the thermal energy transfer and storage characteristics of microwave-absorbing concrete containing magnetite and/or carbonyl iron powder

A microwave-absorbing concrete with favorable heat transfer and storage was investigated to improve the efficiency of deicing concrete pavement during microwave heating and off in cold winter. The concrete was prepared using magnetite and/or carbonyl iron powder (CIP) as the absorbing material. The effect of SiC as the heat transfer and storage material on microwave absorption efficiency, thermal conductivity and thermal diffusivity of concrete were studied. In addition, the pore structures of concrete were investigated to analyze its influence on the thermal properties of concrete.The results showed that the SiC slightly affected the microwave absorption capacity of magnetite concrete (MC) and magnetite-CIP concrete (MCC). The SiC could effectively improve heat transfer and storage ability of concrete. When the content of SiC was 7%, SiC improved the thermal conductivity and effusivity of MC and MCC were improved by 86.4% and 110%, and 84% and 97.3%, respectively. Meanwhile, adding CIP and SiC could improve the porosity and pore diameter of concrete to make it dense, which might be an influence factor to improve the thermal properties of concrete. Under the same conditions, the thermal conductivity and storage capacity of concrete showed the same change trend. In addition, the coefficient of temperature nonuniformity (CTN) and coefficient of max temperature gradient (CMTG) as new indexes was used to evaluate the influence of SiC on the thermal properties of concrete. Therefore, to improve concrete absorption of more heat during microwave heating, and transfer and store heat quickly for road deicing, the magnetite-CIP-SiC concrete (MCSC) might be the most suitable.

Thin layers of microwave absorbing metamaterials with carbon fibers and FeSi alloy ribbons to enhance the absorption properties

In order to break through the bottleneck of narrow effective absorption bandwidth (reflection loss RL ≤ −10 dB) of microwave absorbing materials, herein, we fabricate the metamaterials with carbon fiber (CF) and FeSi alloy (FSA) ribbon metastructure which is distributed in the carbonyl iron powders (CIP)/polyurethane (PU) matrix. The experimental results show that the microwave absorption capacity of the matrix can be significantly enhanced by CF. Compared with the pure matrix, the effective absorption bandwidth increases from 9.4–13.44 GHz to 11–16.8 GHz when the CF is parallel to the electric field vector and the spacing between adjacent CF is 20 mm. Furthermore, the CF and FSA ribbons are arranged in the matrix as an orthogonal arrangement, and the best absorption bandwidth cover 9.76–14.46 GHz when the electric field is parallel and 9.96–14.1GHz when the electric field is vertical when the spacing is 30 mm. The electromagnetic simulation of the metamaterials is calculated, it is proved that the increase of effective absorption bandwidth is due to the strengthening of carbon fiber and its coupling with FSA ribbon. This paper provides a new research path for improving the absorption properties of thin layer microwave absorbing materials.

Hierarchical dandelion-like CoS2 hollow microspheres: self-assembly and controllable microwave absorption performance.

The emerging electromagnetic radiation and interference problems have promoted the rapid development of microwave absorption materials (MAMs). However, it remains a severe challenge to construct high-performance microwave absorption materials with broadband, lightweight and corrosion resistance within low filling contents. Herein, hierarchical dandelion-like CoS2 hollow microspheres were reasonably constructed via a solvothermal-hydrothermal etching-in situ vulcanization process. The structure morphology, composition and electromagnetic performance of all samples have been thoroughly tested. The research results demonstrated that the structure morphology of the prepared samples with a volume ratio of 1 : 1 between ethanol and H2O remained intact without serious damage. Notably, the as-obtained hierarchical dandelion-like CoS2 hollow microspheres (25 wt%) exhibited excellent microwave absorption capacity with a minimum reflection loss (RLmin) of -47.3 dB and the corresponding effective absorption bandwidth (EAB) of 8.4 GHz at 3.3 mm. Moreover, the broadest effective absorption bandwidth (EAB, RL < -10 dB) reached 9.0 GHz (9.0-18.0 GHz) at the matching thickness of 3.2 mm. The unparalleled multiple features including hierarchical hollow structure, tunable complex permittivity as well as the enhanced impedance matching endowed CoS2 great promise as high-performance microwave absorbers for solving the problem of electromagnetic pollution.

Phase Transition Induced via the Template Enabling Cocoon-like MoS2 an Exceptionally Electromagnetic Absorber.

Structural engineering via the template method is efficient for micro-nano assembling. However, only structural design and lack of composition control restrict their advanced application. To overcome this issue, applying a template to simultaneously realize the structural design and fine component control is highly desired, which has been ignored. In this study, a spinel-shaped MoS2 heterostructure with controlled phase ratios of 1H and 2H phase is developed using the AlOOH template method. This work demonstrates that the MoS2 phase transition mechanism from 2H to 1T is substantially attributed to the close exposed crystal's surface and approximately accordant surface energy. The superiority and additional proof are provided based on density-functional theory simulation, transmission electron microscope holography, etc. With an effective absorptance region of 6.3GHz under a thickness of 1.4mm, the reported samples present outstanding microwave absorption capacity. This is attributed to the beneficial coupled effect between the well-designed structure and phase regulation. This work offers valuable insights into structural engineering and component regulation template methods.

Construction of core-shell BN-OH@Fe3O4@PAn nanocomposite with ultra-wide microwave absorption and efficiency thermal management

As electronic device integration and power density increase, materials must have brilliant microwave absorption properties and thermal conductivity to solve electromagnetic wave pollution and thermal management problems. In this work, we attempt to construct core-shell hydroxylated boron nitride nanosheets (BN-OH) @Fe3O4@PAn (BFeA) nanocomposites by chemical synthesis and in-situ growth design. The excellent magnetic properties of Fe3O4 and the good electrical conductivity of PAn can form magnetic loss and electrical loss centers to play a synergistic effect in improving microwave absorption capacity. Meanwhile, with the wave-transmitting material BN-OH as the core, the electromagnetic waves can be reflected multiple times within the absorber, which further enhances the microwave absorption capability of BFeA. As a result, the minimum reflection loss (RLmin) of the composites can reach − 49.85 dB at 11.36 GHz, and the effective microwave absorption bandwidth (RL<−10 dB, EAB) is close to 8 GHz (8.5–16.5 GHz) at a thickness of 3 mm. Simultaneously, to improve the thermal conductivity (TC) of the BFeA and reduce the interfacial thermal resistance, we use hydroxyl and dopamine as the interface linking agent at the interfaces of BN-OH and Fe3O4, and Fe3O4 and PAn, respectively. In this case, the TC of BFeA-2 reaches 0.98 W (m K)−1 at a total BN–OH content of only 13 wt. %, nearly 4 times that of the raw material (Fe3O4). This work can provide a reference for developing materials with dual functions of thermal management and microwave absorption.