Ag-doped PDA interface strategy for selective electron transition integrating EMI shielding and anti-corrosion performance

Metal-based electromagnetic interference (EMI) shielding composites are essential for ensuring electromagnetic compatibility but are often compromised by susceptibility to corrosion, especially in harsh environments. Existing strategies to mitigate coupling corrosion typically involve physical barriers, which inevitably hinder conductivity. In this study, we introduce a novel interface doping approach to fabricate lightweight Graphite@PDA/Ag@Ag composites that simultaneously enhance EMI shielding and corrosion resistance. The PDA/Ag layer selectively regulates electrons with different migration directions and energies to migrate, increasing charge transfer resistance at Ag/graphite interfaces and ensuring conductivity through a tunneling effect. This design achieves an ultralow corrosion rate of 4.313 × 10^–8 µm/y (a billionth that of 316 L stainless steel) alongside superior EMI shielding effectiveness of 109 dB in the X-band at 1.5 mm thickness. Remarkably, the composite maintains over 90 dB shielding efficiency after 7 d in NaCl solutions across various pH levels. Furthermore, simulated corrosion under South China Sea conditions predicts a coating loss of less than 0.026 µm over 7 years. This work presents a transformative approach to mitigating coupling corrosion in EMI shielding materials, offering a practical route to high-performance, corrosion-resistant composites without the need for a protective topcoat.