Facile design of a domestic thermoelectric generator by tailoring the thermoelectric performance of volume-controlled expanded graphite/PVDF composites

Polymer-based thermoelectric materials have attracted considerable interest for green energy conversion over the past decades. In this study, polymer/inorganic thermoelectric generators were prepared by integrating film-forming polyvinylidene fluoride (PVDF) and expanded graphites (EGs) to tailor the thermoelectric performance of the resulting PVDF/EG composites by adjusting the expansion volume of EGs with different thermal treatments. The charge carrier rate and phonon scattering are responsible for the divergent performance of the prepared polymer/EG composites. The prepared composites exhibited superior thermoelectric properties, where the PVDF/EG composite containing 20% EG expanded at 600 °C showed an electrical conductivity of 883 S/cm, a Seebeck coefficient of 8.77 μV/K, and a high power factor of 6.79 μW m⁻¹K⁻². This composite outperforms many other graphene- or graphite-based composites reported in the literature. This study provides a facile avenue to prepare an inexpensive, lightweight, nontoxic, and highly efficient thermoelectric generator for green energy conversion and energy harvesting.