Aramid nanofibers-assisted graphite films for efficient electromagnetic interference shielding

Abstract

Micro-scale graphite has significant application prospects in electromagnetic interference (EMI) shielding compared with conductive nanomaterials (such as graphene, carbon nanotube, and MXene), owing to its low cost, scalability, and large crystalline size. However, the challenges of poor dispersion and film-formation of micro-scale graphite hinder the preparation of highly conductive self-standing graphite-based films. In this study, we effectively solve the dispersion and film-formation issues of micro-scale graphite by introducing a small amount (10 wt%) of aramid nanofibers (ANF), which benefites from the great aspect ratio and high specific surface area of ANF. The resulting graphite/ANF films achieve an ultra-high conductivity of 5323.7 S/m, and their EMI shielding effectiveness (EMI SE) reaches 38.9 dB at a thickness of only 30 μm within the frequency range of 8.2–12.4 GHz. In addition, the graphite/ANF films demonstrate excellent mechanical flexibility, thermal stability, and flame retardancy. This study provides a pathway for assembling micro-scale graphite into highly conductive self-standing films, highlighting their significant potential for EMI shielding applications in electronic equipment.