Phonon Transport Properties Research Articles

Effect of four-phonon scattering on anisotropic thermal transport in bulk hexagonal boron nitride by machine learning interatomic potential

The highly anisotropic thermal conductivity in layered materials is crucial for a broad range of applications such as thermal management of electronic devices, thermal insulation, and thermoelectrics. Understanding of anisotropic thermal transport in layered materials largely depends on atomistic simulations based on density functional theory (DFT) or empirical potentials, which however suffer either low computational efficiency or accuracy. Recently, machine learning interatomic potentials (MLIPs) are emerging as a powerful tool to bridge the gap. Despite the recent progress in developing MLIPs, little attention has been paid to constructing a potential that can accurately predict the thermal properties of layered materials, which is more challenging compared with the case of isotropic materials because of the highly anisotropic bonding and weak van der Waals interactions in layered materials. Here, we introduce a MLIP within the Gaussian approximation potential (GAP) framework for bulk hexagonal boron nitride (h-BN) with a typical layered structure. We demonstrate that the GAP can well predict the highly anisotropic phonon transport properties and thermal conductivity of bulk h-BN with DFT-level accuracy at 3 orders of magnitude reduced cost. Particularly, we investigate the effect of four-phonon scattering on the thermal conductivity of bulk h-BN using the GAP. The suppression of thermal conductivity by four-phonon scattering is negligible below 300 K due to the orders of magnitude weaker four-phonon scattering than three-phonon scattering, which is mainly attributed to the breaking of the reflection symmetry selection rule and the splitting of the flexural acoustic branch in bulk h-BN. As temperature increases, four-phonon scattering results in a larger reduction in thermal conductivity, which increases up to 21.64% (in-plane) and 35.71% (cross-plane) at 1000 K. Atomistic simulations based on MLIPs are expected to be able to greatly promote the understanding of phonon transport and the prediction of thermophysical properties in layered materials.

Realize high thermoelectric properties in n-type Bi2Te2.7Se0.3 materials via ZrO2 ceramic nanoparticles mediated heterogeneous interface

Bismuth telluride (Bi2Te3)-based thermoelectric materials have been commercially utilized for refrigeration and energy conversion at room/near room temperature. However, n-type Bi2Te3 compounds always exhibit inferior performance compared with their p-type counterparts, which is pronouncedly impeding Bi2Te3-based energy converters from further optimizations. Herein, a promising ZT value (ZT = 1.33) was obtained in n-type Bi2Te2.7Se0.3 (BTS) materials by using an interface engineering strategy to synergistically optimize the electron and phonon transport properties. In detail, ZrO2 ceramic nanoparticles (NPs) were entered into BTS matrix to construct high-density heterogeneous interfaces. The heterogeneous interfaces strongly scatter phonons and lower energy carriers, leading to decreased thermal conductivity and increased Seebeck coefficient, while the electrical conductivity is not sacrificed due to the compromise of the slightly reduced carrier mobility by interfacial scattering and the increased carrier concentration by ZrO2 NPs doping. A planar module consisting of 127 pairs of p-n single legs were assembled. At the temperature difference of 200 K, the output power and energy conversion efficiency reached 9.6 W and 6.2%, respectively. This strategy provides a feasible way to rationally design advanced n-type Bi2Te2.7Se0.3 materials with excellent thermoelectric and mechanical properties induced by high-density heterogeneous interfaces.

Effect of Hydrostatic Pressure on Lone Pair Activity and Phonon Transport in Bi2O2S

Dibismuth dioxychalcogenides, Bi2O2Ch (Ch = S, Se, Te), are a promising class of materials for next-generation electronics and thermoelectrics due to their ultrahigh carrier mobility and excellent air stability. An interesting member of this family is Bi2O2S, which has a stereochemically active 6s2 lone pair of Bi3+ cations, heterogeneous bonding, and a high mass contrast between its constituent elements. In the present study, we have used first-principles calculations in combination with Boltzmann transport theory to systematically investigate the effect of hydrostatic pressure on lattice dynamics and phonon transport properties of Bi2O2S. We found that the ambient Pnmn phase has a low average lattice thermal conductivity (κl) of 1.71 W/(m K) at 300 K. We also predicted that Bi2O2S undergoes a structural phase transition from a low-symmetry (Pnmn) to a high-symmetry (I4/mmm) structure at around 4 GPa due to centering of Bi3+ cations with pressure. Upon compression, the lone pair activity of Bi3+ cations is suppressed, which increases κl by almost 3 times to 4.92 W/(m K) at 5 GPa for the I4/mmm phase. The computed phonon lifetimes and Grüneisen parameters show that anharmonicity decreases with increasing pressure due to further suppression of the lone pair activity and strengthening of intra- and intermolecular interactions, leading to an average room-temperature κl of 12.82 W/(m K) at 20 GPa. Overall, this study provides a comprehensive understanding of the effect of hydrostatic pressure on the stereochemical activity of the lone pair of Bi3+ cations and its implications on the phonon transport properties of Bi2O2S.

Enhanced thermoelectric performance of p-type PbTe thin films deposited by magnetron sputtering via incorporating SnS

Incorporating second phase or solid solution into the thermoelectric (TE) material matrix has been proven effective to promote its performance. Recent investigations manifest that the synergistical optimization of the electrical and phonon transport properties could be achieved in the PbTe–SnSe system. Being an analogue of SnSe and more environmental, here, SnS was introduced into p-type PbTe film through intermittent magnetron co-sputtering technique. Small amount SnS was observed to induce the shift of predominant orientation from the (200) plane to the (222) plane as well as distinct change in the surface morphology. After the quite possible SnS solid solution and appropriate subsequent annealing, the electrical conductivity and the power factor (PF) have been optimized prominently. In comparison with that of the pristine PbTe film, the maximum PF has been increased by 217% in the annealed film with the intermediate SnS content.

Mechanochemical Synthesis of Sustainable Ternary and Quaternary Nanostructured Cu2SnS3, Cu2ZnSnS4, and Cu2ZnSnSe4 Chalcogenides for Thermoelectric Applications

Copper-based chalcogenides have emerged as promising thermoelectric materials due to their high thermoelectric performance, tunable transport properties, earth abundance and low toxicity. We have presented an overview of experimental results and first-principal calculations investigating the thermoelectric properties of various polymorphs of Cu2SnS3 (CTS), Cu2ZnSnS4 (CZTS), and Cu2ZnSnSe4 (CZTSe) synthesized by high-energy reactive mechanical alloying (ball milling). Of particular interest are the disordered polymorphs of these materials, which exhibit phonon-glass-electron-crystal behavior-a decoupling of electron and phonon transport properties. The interplay of cationic disorder and nanostructuring leads to ultra-low thermal conductivities while enhancing electronic transport. These beneficial transport properties are the consequence of a plethora of features, including trap states, anharmonicity, rattling, and conductive surface states, both topologically trivial and non-trivial. Based on experimental results and computational methods, this report aims to elucidate the details of the electronic and lattice transport properties, thereby confirming that the higher thermoelectric (TE) performance of disordered polymorphs is essentially due to their complex crystallographic structures. In addition, we have presented synchrotron X-ray diffraction (SR-XRD) measurements and ab initio molecular dynamics (AIMD) simulations of the root-mean-square displacement (RMSD) in these materials, confirming anharmonicity and bond inhomogeneity for disordered polymorphs.

Theoretical Prediction of Thermoelectric Performance for Layered LaAgOX (X = S, Se) Materials in Consideration of the Four-Phonon and Multiple Carrier Scattering Processes.

Inspired by the experimental achievement of layered LaCuOX (X = S, Se) with superior thermoelectric (TE) performance, the TE properties of Ag-based isomorphic LaAgOX are systemically investigated by the first-principles calculation. The LaAgOS and LaAgOSe are direct semiconductors with wide bandgaps of ≈2.50 and ≈2.35eV. Essential four-phonon and multiple carrier scattering mechanisms are considered in phonon and electronic transport calculations to improve the accuracy of the figure-of-merit (ZT). The p-type LaAgOX (X = S, Se) shows excellent TE performance on account of the large Seebeck coefficient originated from the band convergency and low thermal conductivity caused by the strong phonon-phonon scattering. Consequently, the optimal ZTs along the out-of-plane direction decrease in the order of n-type LaAgOSe (≈2.88) > p-type LaAgOSe (≈2.50) > p-type LaAgOS (≈2.42) > n-type LaAgOS (≈2.27) at 700K, and the optimal ZTs of ≈1.16 and ≈1.29 are achieved for p-type LaAgOS and LaAgOSe at the same temperature. The present work would provide a deep insight into the phonon and electronic transport properties of LaAgOX (X = S, Se), but also could shed light on the way for the rational design of state-of-the-art heteroanionic materials for TE application.

Unexpected Enhanced Thermal Conductivity of GaxIn1–xSb Ternary Alloys

Alloying is one of the most common approaches to modulate the properties of semiconductors, such as indium antimonide (InSb) with practical applications in mid-infrared optoelectronics. Thermal conductivity plays a key role in governing the operating performance of devices, and the high-efficiency regulation is of great significance to desirable applications. In this study, we studied the thermal transport properties of InSb, GaSb, and their GaxIn1–xSb alloys by solving the Boltzmann transport equation based on first-principles calculations. The thermal conductivity of GaxIn1–xSb alloys (x = 0.25, κ = 9.21 Wm–1 K–1; x = 0.5, κ = 11.22 Wm–1 K–1; and x = 0.75, κ = 15.45 Wm–1 K–1) is enhanced compared with that of InSb (κ = 5.15 Wm–1 K–1), which is unlike the conventional belief that alloying usually reduces thermal conductivity. Through fundamental analysis of phonon transport properties, the higher phonon group velocity and phonon relaxation time caused by the weak phonon anharmonicity lead to higher thermal conductivity of the GaxIn1–xSb alloys. The weakened polarization of GaxIn1–xSb alloys occurring in the alloying process generates the increased thermal conductivity, which can be figured out by analyzing the orbital-projected electronic density of states and the electron localization functions. The underlying mechanism of unconventional high thermal conductivity of the GaxIn1–xSb alloys in this study would provide guidance for the device applications accompanied by thermal transport.

Strain effect on the phonon transport properties of hydrogenated 2D GaN

Surface hydrogenation on 2D GaN has received extensive attention since surface passivation broadens its application in electronic devices. Strain is inevitably introduced in the process of 2D material synthesis, and its effects on thermal transport need to be discussed. In this work, we performed a detailed study on the strain-dependent thermal transport properties of hydrogenated monolayer GaN (H-GaN). With the increasing of strain, the thermal conductivity of H-GaN rises first and then descends, showing a volcanic shape. Detailed analyses show that the primary factor affecting the trend origins from the change of phonon lifetime. Fundamental understanding of the lifetime trend is achieved by electronic structures. It is found that due to the competition between the polarity and strength of Ga-N bond, atom vibration anharmonicity first drops and then enhances with the increasing of strain. Moreover, mean free path shows that strain combined nanostructure engineering could regulate the thermal transport properties effectively due to size effect.

Electron-phonon coupling, bipolar effects, and thermoelectric performance of the CuSbS2 monolayer.

The thermoelectric performance of the CuSbS2 monolayer is determined using the relaxation times obtained from electron-phonon coupling calculations and the transport properties of phonons and electrons. Based on the fully relaxed structure, the lattice thermal conductivity and the electronic transport coefficients are evaluated by solving the Boltzmann transport equation for phonons and electrons under relaxation time approximation, respectively. The tendencies of the transport coefficients depending on the carrier concentrations and temperatures are studied to understand the thermoelectric performance. Based on the bipolar effect, the transport coefficients and intrinsic carrier concentrations, we determined the dimensionless figure of merit ZT in the 300-800 K range. The results demonstrate that the CuSbS2 monolayer should be an p-type semiconductor, and the maximum ZT of 1.36 is obtained, indicating that the monolayer is a good candidate for high-temperature thermoelectric devices. Substantial bipolar effects are observed, and the ones in the x-direction are stronger in comparison to those in the y-direction, which is responsible for the smaller ZT in the x-direction.

Thermoelectric properties of X3N2O2 (X = Hf, Zr) MXene monolayers: a first-principles study.

MXene monolayers have received increasing attention due to their unique properties, particularly their high conductivity, which shows great potential in thermoelectric materials. In this paper, we present a theoretical study of the thermoelectric properties of X3N2O2 (X = Hf, Zr) MXene monolayers, taking electron-phonon coupling into consideration. Owing to their similar geometrical structures, electronic band structures, and phonon dispersions, X3N2O2 MXene monolayers exhibit homogeneous electron and phonon transport properties. The conduction band shows multi-valley characteristics which leads to better n-type electron transport properties than p-type ones. The maximum values of the n-type power factor can reach 32 μW cm-1 K-2 for the Hf3N2O2 monolayer and 23 μW cm-1 K-2 for the Zr3N2O2 monolayer. In terms of phonon transport, the lattice thermal conductivity for the Zr3N2O2 monolayer is higher than that for the Hf3N2O2 monolayer, due to larger phonon group velocity. Our results show that the Hf3N2O2 monolayer is more suitable for thermoelectric materials than the Zr3N2O2 monolayer, with optimal n-type thermoelectric figure of merit (ZT) values of 0.36 and 0.15 at 700 K, respectively. These findings may be useful for the development of wearable thermoelectric devices and sensor applications based on X3N2O2 MXene monolayers.

Tensile strain and finite size modulation of low lattice thermal conductivity in monolayer TMDCs (HfSe2 and ZrS2) from first-principles: a comparative study.

With excellent physical and chemical properties, 2D TMDC materials have been widely used in engineering applications, but they inevitably suffer from the dual effects of strain and device size. As typical 2D TMDCs, HfSe2 and ZrS2 are reported to have excellent thermoelectric properties. Thermal transport properties have great significance for exerting the performance of materials, ensuring device lifetime and stable operation, but current research is not detailed enough. Here, first-principles combined with the phonon Boltzmann transport equation are used to study the phonon transport inside monolayer HfSe2 and ZrS2 under tensile strain and finite size, and explore the band structure properties. Our research shows that they have similar phonon dispersion curve structures, and the band gap of HfSe2 increases monotonically with the increase of tensile strain, while the bandgap of ZrS2 increases and then decreases with the increase of tensile strain. Thermal conductivity has obvious strain dependence: with the increase of tensile strain, the thermal conductivity of HfSe2 gradually decreases, while that of ZrS2 increases slightly, and then gradually decreases. Reducing the system size can limit the contribution of phonons with a long mean free path, significantly decreasing thermal conductivity through the controlling effect of tensile strain. The mode contribution of thermal conductivity is systematically investigated, and anharmonic properties including mode and frequency-level scattering rates, group velocity and Grüneisen parameters are used to explain the associated mechanism. Phonon scattering processes and channels in various cases are discussed in detail. Our research provides a detailed understanding of the phonon transport and electronic structural properties of low thermal conductivity monolayers of HfSe2 and ZrS2, and further completes the study of thermal transport of the two materials under strain and size tuning, which will provide a foundation for further popularization and application.

The effect of magnetic order on the thermal transport properties of the intrinsic two-dimensional magnet 2H-VSe2.

By using first-principles calculations combined with the phonon Boltzmann transport equation, in this work, we systematically investigate the effect of magnetic order on the phonon and thermal transport properties of the intrinsic two dimensional magnet 2H-VSe2. The results show that 2H-VSe2 is dynamically stable in both paramagnetic and ferromagnetic phases, and the obvious discrepancy of characteristic frequencies of Raman-active phonon modes provides a reliable way to identify the magnetic phase. Meanwhile, our calculations also indicate that the magnetic order has a vital effect on the thermal transport properties. Around the Curie temperature (500 K), the thermal conductivity of 2H-VSe2 in the FM phase (16.3 W mK-1) is about four times larger than that in the PM phase (4.3 W mK-1), and such a difference could be maintained even when considering the temperature dependent force constants. By analyzing the phonon mode information and root mean square displacement, we reveal that large atomic interactions and suppressed phonon anharmonicity are the main roots for the enhanced thermal conductivity in the FM phase 2H-VSe2. These results further demonstrate that magnetic materials with a FM phase always host more excellent thermal transport properties than those with a PM phase, and shed light on the great potential applications of thermal switching devices based on 2H-VSe2.

Determining phonon transport properties of bismuth telluride thin films with extremely small grain size using nanoindentation and 3ω method

The phonon transport properties of Bi2Te3 thin films with extremely small grain size (3.4 nm) is investigated in this study using radio-frequency magnetron sputtering. The films exhibited an average group velocity of 2083 m s−1 and lattice thermal conductivity of 0.42 W (m−1∙K−1), as determined by nanoindentation and 3ω method, respectively. The phonon mean free path (MFP) was 0.49 nm, determined from the group velocity and lattice thermal conductivity. The lattice thermal conductivity decreased to 35% for single-crystal Bi2Te3 owing to the decrease in the phonon MFP, whereas the group velocity hardly changed in the region of extremely small grain size.

Effect of out-of-plane acoustic phonons on the thermal transport properties of graphene

The lattice thermal conductivity of graphene is evaluated using a microscopic model that takes into account the lattice's discrete nature and the phonon dispersion relation within the Brillouin zone. The Boltzmann transport equation is solved iteratively within the framework of three-phonon interactions without taking into account the four-phonon scattering process. The Umklapp and normal collisions are treated rigorously, thereby avoiding relaxation-time and long-wavelength approximations. The mechanisms of the failures of these approximations in predicting the thermal transport properties are discussed. Evaluation of the thermal conductivity is performed at different temperatures and frequencies and in different crystallite sizes. Reasonably good agreement with the experimental data is obtained. The calculation reveals a critical role of out-of-plane acoustic phonons in determining the thermal conductivity. The out-of-plane acoustic phonons contribute greatly and the longitudinal and transverse acoustic phonons make small contributions over a wide range of temperatures and frequencies. The out-of-plane acoustic phonons dominate the thermal conductivity due to their high density of states and restrictions governing the anharmonic phonon scattering. The selection rule severely restricts the phase space for out-of-plane phonon scattering due to reflection symmetry. The optical phonon contribution cannot be neglected at higher temperatures. Both Umklapp and normal processes must be taken into account in order to predict the phonon transport properties accurately.

First-principles study on phonon transport properties of MoTe2 and WTe2 monolayers in different phases

Phase engineering of two-dimensional (2D) transition metal dichalcogenides (TMDC) monolayer is a key method for manipulating the lattice thermal conductivity. In this paper, we investigate the phonon thermal transport properties of MoTe2 and WTe2 monolayers with H and T′ phases (H-TMDC and T′-TMDC) via first-principles calculations. H-MoTe2 and H-WTe2 monolayers have isotropic lattice thermal conductivities, whereas the lattice thermal conductivities of T′-MoTe2 and T′-WTe2 monolayers are highly anisotropic. Meanwhile, in comparison with the H phase, the maximal lattice thermal conductivity in T′ phase has a reduction of 83.85% and 77.92% at 300 K for MoTe2 and WTe2 monolayers, respectively. Furthermore, we observe that phonon heat capacities and phonon lifetimes of T′-TMDC monolayers are lower than those of H-TMDC monolayers, while the phonon group velocities of T′-TMDC monolayers are larger. Hence, the competitive relationship among these parameters leads to a lower lattice thermal conductivity of the T′-TMDC monolayer. In addition, lower critical phonon MFPs (mean free path) of T′-TMDC monolayers prove that the lattice thermal conductivity has a weaker size dependence. These findings demonstrate that MoTe2 and WTe2 monolayers with different phases have a great potential in 2D nanoelectronic devices.

Suppressed thermal conductivity of bilayer SnS: A comparative study among the monolayer, bilayer and bulk SnS

The layer-stacking of 2D materials have been proven to be an effective tool to modulate the low-dimensional electronic structures and transport properties. In this study, the lattice thermal transport properties of bilayer SnS are investigated systematically by solving phonon Boltzmann transport equation based on first-principles calculations. The stacking effect on the in-plane thermal conductivity is further revealed through comparing phonon transport properties of the monolayer, bilayer and bulk SnS. A dramatic suppression of the thermal conductivity, even below 0.5 Wm −1 K −1 per layer at 300 K, can be observed for the fully relaxed bilayer SnS, which implies the great potential for SnS-based thermoelectric applications. The underlying phonon transport mechanisms are also uncovered, and the drop of phonon relaxation time, resulted from the enhanced interlayer anharmonic phonon scattering, is responsible for the suppression of lattice thermal transport. • The stacking stability of bilayer SnS is revealed, and the AA′-stacking is the most dynamically stable configuration for the bilayer SnS. • A dramatically suppressed thermal conductivity for the special stacking configuration of the bilayer SnS, e. g. 0.294 (0.112) Wm −1 K −1 per layer at 300 K along the zigzag (armchair) direction, can be predicted. • The underlying phonon transport mechanisms, and the stacking effects, are also revealed through a comparative study among the monolayer, bilayer and bulk SnS.

Broad Temperature Plateau for High Thermoelectric Properties of n-Type Bi2Te2.7Se0.3 by 3D Printing-Driven Defect Engineering

High-energy-conversion Bi2Te3-based thermoelectric generators (TEGs) are needed to ensure that the assembled material has a high value of average figure of merit (ZTave). However, the inferior ZTave of the n-type leg severely restricts the large-scale applications of Bi2Te3-based TEGs. In this study, we achieved and reported a high peak ZT (1.33) of three-dimensional (3D)-printing n-type Bi2Te2.7Se0.3. In addition, a superior ZTave of 1.23 at a temperature ranging from 300 to 500 K was achieved. The high value of ZTave was obtained by synergistically optimizing the electronic- and phonon-transport properties using the 3D-printing-driven defect engineering. The nonequilibrium solidification mechanism facilitated the multiscale defects formed during the 3D-printed process. Among the defects formed, the nanotwins triggered the energy-filtering effect, thus enhancing the Seebeck coefficient at a temperature range of 300-500 K. The effective scattering of wide-frequency phonons by multiscale defects reduced the lattice thermal conductivity close to the theoretical minimum of ∼0.35 W m-1 k-1. Given the advantages of 3D printing in freeform device shapes, we assembled and measured bionic honeycomb-shaped single-leg TEGs, exhibiting a record-high energy conversion efficiency (10.2%). This work demonstrates the great potential of defect engineering driven by selective laser melting 3D-printing technology for the rational design of advanced n-type Bi2Te2.7Se0.3 thermoelectric material.

Effects of electron-phonon coupling on the phonon transport properties of the Weyl semimetals NbAs and TaAs: A comparative study

It has now become recognized that the electron-phonon coupling (EPC) may play an important role in governing the phonon transport, especially for metallic and semiconducting systems at high carrier concentration. Here we focus on the Weyl semimetals TaAs and NbAs and give a comparative study on their phonon transport properties by explicitly including the EPC in first-principles calculations. It is found that the lattice thermal conductivities of both systems are significantly reduced by the EPC, which is more pronounced for the TaAs compared with the NbAs at the same carrier concentration. Detailed analysis indicates that the TaAs exhibits smaller EPC phonon relaxation time, as characterized by stronger EPC strength which is associated with larger deformation potential constant and Born effective charge. Moreover, we see that the TaAs exhibits obviously larger overlap between the EPC relaxation time and that from intrinsic phonon-phonon scattering, which could further reduce the lattice thermal conductivity. Our work not only highlights the vital importance of EPC in accurately predicting the phonon transport behaviors, but also offers a simple alternative to evaluate the EPC strength of various material systems.

Mechanism of the low thermal conductivity in novel two-dimensional NaCuSe

Low lattice thermal conductivity is crucial to obtain an excellent thermoelectric figure of merit (ZT) in thermoelectric (TE) materials. Herein, we study the phonon transport properties of two-dimensional (2D) NaCuSe using first-principles calculations. NaCuSe has an intrinsically low lattice thermal conductivity, 2.46 W/mK at 300 K, which originates from its low mean sound velocity (vm) and strong phonon anharmonicity. By utilizing the crystal orbital Hamilton population (COHP) analysis, we attribute low vm to the filling of anti-bonding orbitals between Cu-3d and Se-4p states, giving rise to the weak chemical bonds. Also, this research investigates the scattering processes (the out-of-plan acoustic mode (ZA) + optical mode(O) → O(ZA + O → O), the in-plane transverse acoustic mode (TA) + O → O(TA + O → O), and the in-plane longitudinal acoustic mode (LA) + O → O(LA + O → O). The results demonstrate that NaCuSe is of strong phonon anharmonicity, which could guide to discover and design of new TE materials.

Impedance-matched (hydroxylated nano-BN/reduced graphene oxide) @Fe3O4/polyaniline composite for efficient microwave absorption and thermal management

A microwave absorbing composite material with good thermal conductivity has been prepared to solve the problem of electromagnetic wave pollution in high-power density electronic equipment without increasing the heat load of the equipment. Herein, we prepared the quaternary absorbing material hydroxylated boron nitride nanosheets (BN-o)/reduced graphene oxide (r-GO) @Fe3O4@polyaniline (PAn) (BCFA) and adjusted the content of PAn to enhance the impedance matching and modulate the microwave absorption effect. At a PAn content of 40 wt%, the absorber exhibits admirable microwave absorption performance, the lowest reflection loss (RLmin) of −54.72 dB and effective microwave absorption bandwidth (RL < −10 dB, EAB) of 3.12 GHz at a thickness and frequency of 3.5 mm and 7.2 GHz, respectively. The excellent microwave absorption is due to a suitable mechanism of dielectric and magnetic losses and the excellent impedance matching of the absorber. Moreover, the high thermal conductivity and phonon transport properties of the BN-o/r-GO van der Waals heterostructure give the composite thermal conductivity of 1.69 W(m·K)−1 when the BN-o/r-GO content is approximately 14 wt%. Therefore, BCFA has become a candidate material to solve the electromagnetic pollution problem of high-power density electronic equipment.