Polymer‐Assisted Co‐Exfoliation‐Assembly of Pristine Graphene‐Based Films for Integrated Terahertz Shielding and Thermal Management

Abstract The rapid development of terahertz (THz) technology in sensing, imaging, and emerging 6G systems has created an urgent demand for ultrathin, lightweight, and flexible materials that can simultaneously provide high‐performance electromagnetic interference (EMI) shielding and efficient thermal management. 2D material films are promising candidates, yet scalable fabrication of such films that combine these properties with long‐term stability remains challenging. Here, the study reports a polymer‐assisted co‐exfoliation‐assembly strategy to construct pristine graphene‐based films, where sodium alginate (SA) ensures structural stability through ionic crosslinking and carboxymethyl cellulose (CMC) promotes efficient exfoliation and uniform dispersion within the polymer. The subsequent Ca 2+ crosslinking further reinforces the composite architecture, leading to a continuous conductive network with enhanced durability. As a result, the ≈40 µm‐thick films exhibit a THz shielding effectiveness of 97.7 dB and an in‐plane thermal conductivity of 92.0 W m −1 K −1 , while retaining mechanical flexibility and year‐long ambient stability. The scalable fabrication and multifunctional integration highlight the promise of these films for next‐generation devices requiring integrated EMI shielding and thermal management.