Reduced graphene oxide-polyaniline composites—synthesis, characterization and optimization for thermoelectric applications

Abstract

Reduced graphene oxide (rGO) can improve the thermoelectric properties of polyaniline (PANI) by varying its concentration in composites of rGO nanosheets and PANI. The figure of merit (ZT) of rGO-PANI composites is increased with an increasing percentage of rGO (up to 50%), which is 7.5 times higher as compared to pure PANI. High resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analyses show a uniform growth of PANI over the surface of rGO as a template, leading to a more ordered structure with high crystallinity during polymerization. Compared to pure PANI, both the electrical conductivity and thermoelectric power of the rGO-PANI composite is higher due to the increased carrier mobility as confirmed by a Hall effect measurement. Fourier transform infrared spectroscopy (FTIR), ultra-violet visible range spectroscopy (UV-Vis) and Raman spectroscopy analyses reveal that strong p-p interactions assisted the uniform distribution of PANI on the rGO nanosheets. Other strong interactions include electrostatic forces and hydrogen bonding between rGO and PANI, which provide a route for constructing highly ordered chain structures with improved thermoelectric performance of PANI. There is no significant change in the thermal conductivity of the rGO-PANI composite as compared to pure PANI, which improves the thermoelectric performance of composite.

Composite of polyaniline‐bismuth selenide with enhanced thermoelectric performance

“…PANI‐Bi 2 Se 3 composites were prepared using conventional template‐based in situ oxidative chemical polymerization of aniline with BS NPs template. Total volume of 2 mL aniline (Merck, India) with 5.02 g ammonium persulfate (APS as oxidant, Merck, India) was oxidized in an acidic aqueous medium.…”

“…Conducting polymers‐like polyaniline (PANI), polyhexathiophene (PEDOT), polypyrrole,and so on have unique features like intrinsically low thermal conductivity, abundantly available materials (low cost), nominal density, lightweight, and relatively easy synthesis process addition of carbon nanofillers (e.g., CNTs, graphene, etc. ), using high‐TE‐performance inorganic semiconductors, metal coordination polymers, polymer blends, etc.…”

Fiber‐Based Thermoelectric Generators: Materials, Device Structures, Fabrication, Characterization, and Applications

“…Graphene, [105][106][107][108][109] rGO, [110] multiwalled carbon nanotubes (MWNTs), [111][112][113][114] and single-walled carbon nanotubes [72,73,115] have been hybridized with PANI to produce improved TE properties. Graphene, [105][106][107][108][109] rGO, [110] multiwalled carbon nanotubes (MWNTs), [111][112][113][114] and single-walled carbon nanotubes [72,73,115] have been hybridized with PANI to produce improved TE properties.…”

Thermoelectric performances of graphene/polyaniline composites prepared by one-step electrosynthesis

“…It is likely that the conductivity decrease is due to overoxidation of PANI on the SUS electrode. 22 It is also much greater than those for PANI alone. 5B.…”

“…1 However, the high TE performances of them tend to be realized only at increased temperatures beyond 400 C, although a large part of exhaust heat from households as well as chemical plants, socalled low-temperature exhaust heat, is known to be below 200 C and thus TE materials efficient at low temperatures are needed for practical applications. [15][16][17][18][19][20][21][22] In the present study, graphene/PANI composites prepared by a simple electrochemical technique developed earlier for producing electrochemical capacitors are investigated from the viewpoint of their application to TE materials. Very recently, an increasing number of studies have been devoted to organic alternatives to inorganic TE materials.…”