Formation Mechanism of Hierarchically Porous Graphitic Aerogel and Their Application in EMI Shielding

Hierarchically porous graphitic sheet-based aerogels (HGAs) have garnered significant attention due to their diverse applications in water purification, energy storage, electromagnetic interference (EMI) shielding, and other fields. However, current fabrication methods face sustainability and scalability challenges. This study introduces the formation mechanism of a novel, green synthesis approach for HGAs using naturally available protein precursors. Through in-situ characterization techniques, we elucidate a self-foaming mechanism during controlled pyrolysis. In this process, protein precursors undergo softening, gas evolution, and foaming, followed by carbonization and graphitization, resulting in a hierarchically porous graphitic aerogel with an integrated framework of sheets and fibers. By systematically exploring processing-structure-property relationships, we tailored critical material performance metrics, including density, porosity, and electrical conductivity. The bio-derived HGAs exhibit exceptional EMI shielding performance, with a specific shielding effectiveness per unit thickness (SSE/t) exceeding 16,400 dBcm^2/g, surpassing previously reported carbon and graphene aerogels. This work paves the way for scalable production of HGAs in next-generation technologies, offering a promising solution for various applications, including high-performance EMI shielding.