Graphite‐ PVDF Composite Sheets Fabricated via a Facile and Scalable Technique for Electrical and EMI Shielding Applications

ABSTRACT Composites with suitable electrical properties for electromagnetic interference (EMI) shielding are in great demand for the emerging 5G wireless technology. To meet this demand, an energy‐efficient and scalable method of preparing Graphite‐polyvinylidene fluoride (PVDF) composite sheets was devised. The composites were characterized for their phase, thermal stability, and mechanical strength. XRD and FTIR revealed a comparable α:β phase fractions of PVDF. TGA‐DSC analysis confirmed thermal stability until 160°C. Mechanical compression tests proved that the composite sheets had compression and puncture strengths higher than 520 N. The electrical conductivity of the composites was increased over the range of 10 ⁻⁷ to 1 S/m by systematically varying the graphite concentration from 0 to 40 wt%. Conductive percolation was achieved around 25 wt% graphite. High dielectric constant and tangent losses were attained around the percolation threshold concentration of 25%–30% graphite, making the shields effective for EM wave attenuation. Total shielding effectiveness of 30–50 dB that meets industry standards was achieved for 20%–40% graphite in the X‐band microwave region, with the 30 wt% graphite sample exhibiting the maximum absorbance (A%) of 42%. The absorption part (SE _A ) of total shielding effectiveness reached 86%. The electrical properties were analyzed in detail and correlated with the mechanisms contributing to the EMI shielding performance.