Exploring Graphene's Impact on Graphite/PANI Matrix Composites: High-Press Fabrication and Enhanced Thermal-Electrical Properties

Abstract

This study investigates the effects of graphene content and applied press on electrical and thermal conductivities of graphite/polyaniline (GP) and graphite/graphene/polyaniline (GGP) composites which were produced by using direct mixing method. Based on electrical and thermal conductivity results, 14 wt. % graphene content was found out to be the crucial threshold, beyond which extra graphene additions exhibit different behavior in pressed and unpressed samples. While the electrical conductivity of unpressed samples increase up to 14 wt. % graphene addition, the thermal conductivity increases further after 14 wt. % graphene addition. The addition of graphene induces notable changes in electronic configurations of quinoid and benzenoid rings, as evidenced by ATR-FT-IR spectroscopy. Based on XPS data, the addition of graphene into graphite/PANI-CSA matrix affects electronic distribution and charge transfer mechanisms within GGP composites, particularly showing the impact of graphene addition on the electronic structure of PANI-CSA in GGP-14 527 MPa sample. Importantly, the interlocking of graphene and graphite layers observed in GGP-14 sample pressed at 527 MPa according to Raman and XRD data, leads to enhanced thermal (2253 W m⁻¹K⁻¹), and electrical (210 S cm⁻¹) conductivity. The interlocked configuration of graphene and graphite in GGP-14 527 MPa facilitates efficient electron and phonon flow throughout hexagonal C=C rings and partially charged nitrogen and oxygen atoms of PANI-CSA. In future works, the concept of interlocked graphene and graphite layers can be used to further enhance thermal and electrical properties in thermoelectric material applications.