Dual-interface built-in electric fields induced by sulfidation-driven ordered arrays in MoS₂@C/CoSₓ for high-efficiency microwave absorption

Rational design of hierarchical structures and a dual-interface built-in electric field (BIEF) are vital for enhancing dielectric loss and directional charge transport in microwave absorption materials (MAMs). Herein, we propose a dual-interface BIEF engineering strategy to construct a multifunctional MoS₂@C/CoS_x composites. Inspired by the spiderweb hunting mechanism, magnetic Co-based Prussian blue (PB) is electro spun with polyacrylonitrile to form Co@CoO/C nanofibers, followed by sulfidation to induce ordered array architectures. The structural evolution enables the formation of heterogeneous MoS₂-CoS_x-C interfaces and modulates the interfacial electric field intensity to enhance dielectric polarization. Density functional theory (DFT) calculations confirm that the work function difference (ΔΦ) of C/CoS₂/MoS₂ is 6.179 eV, which indicates that the differences ΔΦ among MoS₂, CoS_x and C components drive the spontaneous formation of dual-interface BIEF. This facilitates directional charge migration and strong dipolar/interface polarization, significantly improving the microwave attenuation capability. Benefiting from this design, the composite achieves a minimum reflection loss (RL_min) of –63.83 dB and a maximum effective absorption bandwidth (EAB_max) of 6.96 GHz, covering both C and Ku bands. In addition, the material reveals excellent infrared stealth performance due to its unique spiderweb-inspired ordered array structure. This study provides new insights into interfacial electric field modulation and a generalizable approach for designing multi-band and tunable microwave absorbers with synergistic electromagnetic and thermal stealth functions.