The directional arrangement of two-dimensional thermally conductive fillers can fully exploit their anisotropic advantages and form efficient thermal conduction paths within the composites, thereby significantly improving their thermal conduction efficiency. In this study, “point-surface” hetero-structured boron nitride nanosheets (BNNS)@Ni thermally conductive fillers with magnetic response are synthesized via in-situ growth and high-temperature carbonization. The H-BNNS@Ni/PDMS (BNNS@Ni horizontally arranged in the polydimethylsiloxane (PDMS) matrix) thermally conductive composites are fabricated via magnetic field orientation. When the mass ratio of BNNS to Ni in BNNS@Ni is 8:1 and the mass fraction of BNNS@Ni is 50 wt.%, the in-plane thermal conductivity (λ_∥) of H-BNNS@Ni/PDMS thermally conductive composites reaches 5.50 W/(m·K), which is 27.8 times higher than that of pure PDMS (0.19 W/(m·K)), and is also significantly higher than that of R-BNNS@Ni/PDMS (BNNS@Ni randomly distributed in the PDMS matrix) thermally conductive composites (4.76 W/(m·K)) with the same mass fraction of BNNS@Ni. H-BNNS@Ni/PDMS thermally conductive composites can reduce the operating temperature at full power by 19.2 °C compared to pure PDMS when used for CPU cooling. Meanwhile, H-BNNS@Ni/PDMS thermally conductive composites also exhibit excellent thermal resistance, photothermal conversion performance, and hydrophobicity.

Ag nanoparticles were in-situ grown on the surface of MXene nanosheets to prepare thermally conductive hetero-structured MXene@Ag fillers. With polyvinyl alcohol (PVA) as the polymer matrix, thermally conductive MXene@Ag/PVA composite films were fabricated by the processes of solution blending, pouring, and evaporative self-assembly. With the same mass fraction, MXene@Ag-III (MXene/Ag, 2:1, w/w) presents more significant improvement in thermal conductivity coefficient (λ) than MXene@Ag, single MXene, Ag, and simply blending MXene/Ag. MXene@Ag-III/PVA composite films show dual functions of excellent thermal conductivity and electromagnetic interference (EMI) shielding. When the mass fraction of MXene@Ag-III is 60 wt.%, the in-plane λ (λ_∥), through-plane λ (λ_⊥), and EMI shielding effectiveness (EMI SE) are 3.72 and 0.41 W/(m∙K), and 32 dB, which are increased by 3.1, 1.3, and 105.7 times than those of pure PVA film (0.91 and 0.18 W/(m∙K), and 0.3 dB), respectively. The 60 wt.% MXene@Ag-III/PVA composite film also has satisfying mechanical and thermal properties, with Young’s modulus, glass transition temperature, and heat resistance index of 3.8 GPa, 58.5 and 175.3 °C, respectively.

Microwave absorbing materials (MAMs) has been intensively investigated in order to meet the requirement of electromagnetic radiation control, especially in S and C band. In this work, FeCo-based magnetic MAMs are hydrothermally synthesized via a magnetic-field-induced process. The composition and morphology of the MAMs are capable of being adjusted simultaneously by the atomic ratio of Fe²⁺ to Co²⁺ in the precursor. The hierarchical magnetic microchain, which has a core–shell structure of two-dimensional Fe_xCo_1−xOOH nanosheets anchored vertically on the surface of a one-dimensional (1D) Co microchain, shows significantly enhanced microwave absorption in C band, resulting in a reflection loss (R_L) of lower than −20 dB at frequencies ranging from 4.4 to 8.0 GHz under a suitable matching thickness. The magnetic coupling of Co microcrystals and the double-loss mechanisms out of the core-shell structure are considered to promote the microwave attenuation capability. The hierarchical design of 1D magnetic MAMs provides a feasible strategy to solve the electromagnetic pollution in C band.

Highly thermal conductivity materials with excellent electromagnetic interference shielding and Joule heating performances are ideal for thermal management in the next generation of communication industry, artificial intelligence and wearable electronics. In this work, silver nanowires (AgNWs) are prepared using silver nitrate as the silver source and ethylene glycol as the solvent and reducing agent, and boron nitride (BN) is performed to prepare BN nanosheets (BNNS) with the help of isopropyl alcohol and ultrasonication-assisted peeling method, which are compounded with aramid nanofibers (ANF) prepared by chemical dissociation, respectively, and the (BNNS/ANF)-(AgNWs/ANF) thermal conductivity and electromagnetic interference shielding composite films with Janus structures are prepared by the “vacuum-assisted filtration and hot-pressing” method. Janus (BNNS/ANF)-(AgNWs/ANF) composite films exhibit “one side insulating, one side conducting” performance, the surface resistivity of the BNNS/ANF surface is 4.7 × 10¹³ Ω, while the conductivity of the AgNWs/ANF surface is 5,275 S/cm. And Janus (BNNS/ANF)-(AgNWs/ANF) composite film with thickness of 95 µm has a high in-plane thermal conductivity coefficient of 8.12 W/(m·K) and superior electromagnetic interference shielding effectiveness of 70 dB. The obtained composite film also has excellent tensile strength of 122.9 MPa and tensile modulus and 2.7 GPa. It also has good temperature-voltage response characteristics (high Joule heating temperature at low supply voltage (5 V, 215.0 °C), fast response time (10 s)), excellent electrical stability and reliability (stable and constant real-time relative resistance under up to 300 cycles and 1,500 s of tensile-bending fatigue work tests).