Highly Thermally Conductive Flexible Films with Excellent Energy Harvesting and Electromagnetic Shielding Properties

Abstract The continuous advancement and miniaturization of modern electronics have increased challenges related to electromagnetic interference (EMI) and thermal management. Polymer materials are commonly used for thermal regulation and EMI shielding because of their low weight, cost‐effectiveness, and ease of processing. However, achieving both high electromagnetic shielding effectiveness (SE) and superior thermal conductivity (TC) in polymeric systems remains a major scientific challenge. In this study, a lightweight and flexible amino‐functionalized multiwalled carbon nanotube‐graphene nanoplatelet/poly(p‐phenylene benzodioxazole)/poly(ether‐ether‐ketone) composite film (NH 2 ‐MWCNTs&GnPs@PBO/PEEK, NH 2 ‐MGPP) is fabricated using vacuum‐assisted filtration. As a result, the NH 2 ‐MGPP film (0.05 mm thick) exhibited exceptional EMI shielding performance (71.47 dB) and in‐plane thermal conductivity (36.78 W m −1 K −1 ). The composite also demonstrated rapid Joule heating kinetics and an efficient photothermal response, enabling effective thermal management and energy harvesting capabilities. When integrated into a solar‐thermoelectric generator, the NH 2 ‐MGPP film produced an output voltage of 1004.9 mV under 5 kW m −2 simulated sunlight irradiation, confirming its high photo‐thermal‐electrical energy conversion efficiency. This study presents an innovative approach for designing and developing flexible composite films with excellent electromagnetic shielding properties and efficient heat dissipation capabilities. Additionally, it introduces a new method for the effective utilization of renewable energy.