Fabrication of Highly Conductive Porous Fe3O4@RGO/PEDOT:PSS Composite Films via Acid Post-Treatment and Their Applications as Electrochemical Supercapacitor and Thermoelectric Material

Abstract

As a remarkable multifunctional material, ferroferric oxide (Fe3O4) exhibits considerable potential for applications in many fields, such as energy storage and conversion technologies. However, the poor electronic and ionic conductivities of classical Fe3O4 restricts its application. To address this challenge, Fe3O4 nanoparticles are combined with graphene oxide (GO) via a typical hydrothermal method, followed by a conductive wrapping using poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic sulfonate) (PEDOT:PSS) for the fabrication of composite films. Upon acid treatment, a highly conductive porous Fe3O4@RGO/PEDOT:PSS hybrid is successfully constructed, and each component exerts its action that effectively facilitates the electron transfer and subsequent performance improvement. Specifically, the Fe3O4@RGO/PEDOT:PSS porous film achieves a high specific capacitance of 244.7 F g−1 at a current of 1 A g−1. Furthermore, due to the facial fabrication of the highly conductive networks, the free-standing film exhibits potential advantages in flexible thermoelectric (TE) materials. Notably, such a hybrid film shows a high electric conductivity (σ) of 507.56 S cm−1, a three times greater value than the Fe3O4@RGO component, and achieves an optimized Seebeck coefficient (S) of 13.29 μV K−1 at room temperature. This work provides a novel route for the synthesis of Fe3O4@RGO/PEDOT:PSS multifunctional films that possess promising applications in energy storage and conversion.

A Novel and Green Method for Preparing Highly Conductive PEDOT:PSS Films for Thermoelectric Energy Harvesting

“…Figure 3 a displays the Raman spectra of the PEDOT:PSS films including the pristine as-prepared one and those treated with different cycles of the water washing treatment. Characteristic peaks associated with PEDOT:PSS structures were observed, with the peak attributions summarized in Table 1 [ 28 , 29 ]: peaks centered at 1566 cm –1 and 1493 cm –1 , corresponding to asymmetric C α =C β stretching, became increasingly prominent after the water treatment; the peak at 1428 cm –1 , attributed to symmetric C α =C β (–O) stretching vibrations of the five-membered thiophene ring, became sharper and more intense. Similar trends were observed at 1367 cm –1 (C β –C β stretching), 1254 cm –1 (inter-ring C α –C α stretching), 1117 cm –1 (C–C ring bending vibration), 1094 cm –1 (C–O–C deformation), 701 cm –1 (symmetric C–S–C deformation), 437 cm –1 (SO 2 bending), 988 cm –1 , and 576 cm –1 (deformation of oxyethylene ring).…”