Nanoporous Conductive Carbon Films via High‐Carbon‐Yield Carbonization of Poly(p‐phenylene benzobisoxazole) Nanofibers

ABSTRACT High‐carbon‐yield precursors are crucial for producing stable carbon materials that retain porous architectures after high‐temperature treatment. Here, we demonstrate that a rigid‐rod polymer, poly(p‐phenylene benzobisoxazole) (PBO) nanofiber networks yield nanoporous carbon films upon carbonization at 700°C–1000°C, achieving high structural integrity and specific surface area (279 m 2 /g). The high carbon yield of PBO preserves the interconnected nanofiber network and promotes the formation of graphitized carbon domains. A clear disorder‐to‐order transition with reduced heteroatom defects is observed at elevated temperatures. These structural evolutions enhance thermal conductivity from 27.2 to 63.2 W/m K and electrical conductivity to 2160 S/m, enabling rapid and stable Joule heating. The resulting nanoporous carbon films exhibit a high electromagnetic interference (EMI) shielding efficiency of 39.8 dB, primarily governed by multiple internal reflections and dielectric losses. This study highlights the significance of high‐carbon‐yield precursors for lightweight, porous, and conductive carbon films for efficient EMI shielding and thermal management.