Simultaneous enhancement of thermal conductivity and EMI shielding in silicone rubber composites enabled by upcycled pyrrhotite tailings and S doped carbon nitride heterojunctions

Pyrrhotite tailings are upcycled into multifunctional silicone rubber composites. • S-doping induces robust SCN/Pyr heterojunctions via Fe-S-C interfacial linkages. • SCN nanosheets serve as phonon bridges to significantly reduce interfacial thermal resistance. • Simultaneous achievement of high TC (1.63 W/m·K) and EMI shielding (40 dB). The relentless miniaturization and densification of modern electronics have precipitated an urgent demand for materials that offer both efficient thermal management and robust electromagnetic interference (EMI) shielding. While utilizing industrial waste for such high-performance applications presents a sustainable pathway, bridging the performance gap in traditional polymer composites remains a challenge due to high interfacial thermal resistance. Herein, we propose a functionalization of waste strategy by engineering a multifunctional silicone rubber (SR) nanocomposite that synergizes pyrrhotite (Pyr) tailings with S doped graphitic carbon nitride (SCN). Specifically, SCN serves as a functional bridge, creating a heterojunction with Pyr that optimizes interfacial compatibility and phonon transport. Consequently, the fabricated SCN/Pyr/SR composite delivers a high thermal conductivity (TC) 1.63 W/(m·K) alongside outstanding electrical insulation with a resistivity exceeding 10 10  Ω·m. Furthermore, it delivers EMI shielding effectiveness of up to 40 dB in the 8.2–12.4 GHz frequency range with absorption being the main mechanism, underscoring its excellent shielding capability. Beyond these primary metrics, the composite demonstrates exceptional reliability in terms of thermal cycling stability, mechanical performance, and water resistance. This work not only provides a high-efficiency solution for thermal and EMI management, but also validates a sustainable route for upcycling bulk sulfide solid wastes to improve the environmental friendliness and the application potential of the composite. Download: Download high-res image (151KB) Download: Download full-size image