Ultraconductive carbon film/fiberboard heterostructure integrating superior EMI shielding and efficient joule heating

Miniaturization and high integration density in electronic devices exacerbate electromagnetic interference (EMI) and thermal management challenges. Here, we develop a multifunctional carbon-based composite integrating efficient EMI shielding and low-energy Joule heating. A unique carbon film/fiberboard heterostructure (GPCFB) is constructed via interface-engineered co‑carbonization of renewable fiberboard with a glucose-polyacrylamide (PAM) precursor. GPCFB achieves an ultrahigh electrical conductivity of 95,880 S·m⁻¹ and an EMI shielding effectiveness (EMI SE) of 80 dB in the X-band (8.2–12.4 GHz), which remains stable under harsh chemical and extreme temperature shocks. Importantly, the integrated carbon film and carbonized fiberboard framework form a heterogeneous architecture that simultaneously provides an efficient conductive network and anisotropic thermal transport behavior. The ultrahigh electrical conductivity enables efficient Joule heat generation, while the higher in-plane and lower through-plane thermal conductivities regulate heat distribution, suppress heat dissipation toward the substrate, and improve electrothermal energy utilization. This allows rapid heating up to 312.0 °C at 4 V with an active de-icing efficiency 3.3 times that of natural melting. This work presents a structurally integrated carbon heterostructure that combines high-efficiency EMI shielding with low-power Joule heating, offering a practical material strategy for applications requiring structural rigidity, environmental stability, and reliable thermal management.