An efficient thermoelectric material: preparation of reduced graphene oxide/polyaniline hybrid composites by cryogenic grinding

Abstract

An alternative and facile strategy to fabricate conducting reduced graphene oxide/polyaniline (rGO/PANI) hybrid composites with highly enhanced thermoelectric properties is introduced. rGO and PANI were homogeneously mixed by cryogenic grinding and then consolidated via spark plasma sintering. X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and transmission electron microscopy were employed to evaluate the phase structure and microstructure of the as-prepared composites. The results show that the CG technique could not only effectively refine the grain size of PANI, but also could induce more dislocations. The refined PANI particles are homogeneously dispersed and orderly arranged on the rGO templates as a result of the strong π–π conjugated interactions between PANI and rGO. The thermoelectric properties of the PANI samples containing different rGO content were systematically investigated. Compared with pure bulk PANI, rGO/PANI hybrid composites exhibit a distinct enhancement in the thermoelectric performance. Both the Seebeck coefficient and the electric conductivity were found to increase remarkably, resulting from the increased carrier mobility. The maximum Seebeck coefficient and electric conductivity of the rGO/PANI hybrid composites amazingly reached 15.934 μV K⁻¹ and 1858.775 S m⁻¹, respectively, and the maximum ZT was up to 4.23 × 10⁻⁴.