Graphene-driven boost of piezoelectric performance in tri-component epoxy/SbSI/graphene nanocomposites

This study reports the first investigation of the influence of graphene incorporation on the electrical and piezoelectric properties of epoxy/SbSI (EP/SbSI) nanocomposites (NCs). Graphene-enhanced composites (EP/G/SbSI) exhibit systematically increased electrical conductivity, improved charge transport, and reduced RC time constants, enabling faster charge dissipation and stable signal generation at higher excitation frequencies. Piezoelectric characterization reveals a significant enhancement of the effective piezoelectric coefficient and pressure sensitivity, rising from 2.11 pC/N and 19.9 mV/bar for EP/SbSI to 37.3 pC/N and 358 mV/bar for EP/20 G/SbSI, while the intrinsic SbSI piezoelectricity remains unchanged. Frequency-dependent measurements reveal power densities of ∼40 W/m³, peaking above 1 kW/m³ at 70–80 Hz, indicating a shift in the optimum response and stable electromechanical performance at higher frequencies due to graphene incorporation. The underlying mechanisms of charge transfer and piezoelectric behaviour have been proposed. These results highlight the synergistic role of graphene in enhancing charge transport, domain structure, and overall energy-harvesting efficiency, indicating the potential of EP/G/SbSI NCs for self-powered piezoelectric applications.