Regulating interfacial charge behavior in multiphase heterostructures is crucial for achieving high-performance electromagnetic wave (EMW) absorption, yet the synergistic optimization of dielectric loss and impedance matching remains a major challenge. Herein, a phosphorus (P) atom doping strategy is proposed to modulate the interfacial properties of a multiphase Co₂N/Co₃S₄/VN/VS heterostructure. P-doping reconstructs the heterointerfaces, promotes charge redistribution, and generates abundant polarization centers, thereby simultaneously optimizing charge transport and polarization relaxation. Density functional theory (DFT) calculations further reveal the vital role of interfacial charge redistribution in boosting polarization behavior. Consequently, the optimized P-CVNS heterostructure achieves a reflection loss (RL) of −36.93 dB and an effective absorption bandwidth (EAB) of 4.0 GHz at a matching thickness of 2.4 mm. This work reveals the pivotal role of heteroatom-doped interface engineering in optimizing EMW absorption and presents a scalable strategy for designing high-performance absorbers.

As electrical equipment is progressively advancing towards high-power and large-capacity integration, the electrical insulation components frequently experience severe structural damage and performance degradation when they are exposed to significant voltage impact. Modifying the insulating base materials through filling to enhance their corona resistance is a critical measure to ensure the safe operation of electrical equipment. This article proposes, for the first time, a distinct modification strategy of cage-like octa(aminopropyl) silsesquioxane (8NH₂-POSS) particle toward the molecular structure of polyimide. This particle can form covalent bonds with both the main chains and side chains of polyimide (PI) during polymerization, thereby enhancing the flame retardant, mechanical and corona resistance of the polyimide matrix. Benefiting from the organic-inorganic hybrid structure, the POSS with amino groups provides interfacial compensation for PI at the molecular structural level. The power frequency breakdown strength of the 8NH₂-POSS main-chain grafted PI composite film (8NMP/PI) is increased by 31.5%, and the corona discharge inception voltage is enhanced from 1.93 to 2.13 kV. And the average corona resistance time of 8NMP/PI is prolonged from 305 to 498 s, which is 63.3 % higher than the pure PI film. Meanwhile, its excellent interface effect improves the flexibility of the composite film, with the average tensile strength increased by 17.6% and the elongation at break by 16.2 %. All composite films have reached UL-94 V-0 rating. This work provides valuable reference for developing high-performance polymer composites for applications in large-scale electrical devices.