Investigation of Electrical and Thermal Conductivity Properties of Polypyrrole Based Composites for Room Temperature Thermoelectric Applications

Abstract

The continuous consumption of fossil fuels and limitations of natural resources newlinehas led to a global challenge in energy and environment. The increasing population has newlineelevated the demand for energy and renewable sources. Among potential solutions, newlinethermoelectric (TE) technology stands out as an emission-free energy conversion newlinetechnique. Thermoelectric materials enable the direct conversion of thermal energy into newlineelectrical energy making them promising candidate for recovering waste/low heat newlineenergy. In this regard, various thermoelectric materials (organic, inorganic, TMDs etc.) newlinehave been studied with significant findings. Among them, conducting polymers and its newlinecomposite materials have been studied as effective alternative materials for room newlinetemperature and flexible thermoelectric application. This work investigate the newlinethermoelectric properties of polypyrrole (PPy) with different morphologies (particle and newlinetube), polypyrrole/polyaniline (PPy/PANI), polypyrrole/carbon black (PPy/CB), and newlinepolypyrrole/polyaniline/carbon black (PPy/PANI/CB) composites. newlineInitially, PPy with various morphologies including particle and tube were newlinesuccessfully prepared via chemical oxidative polymerization. The role of morphology newlineon the thermoelectric properties of PPy was systematically studied. The structural, and newlinecompositional analyses carried out by the XRD, FTIR, and XPS techniques confirmed newlinethe successful formation of PPy. The morphological characterization done by HRSEM newlineand HRTEM analyses revealed the formation of PPy in particle-like and tube-like newlineforms. Hall measurement result revealed that PPy tube structure had better charge newlinetransport properties than PPy particle due to its high carrier concentration (6x1019 cm-3) newlineand high mobility (23.5 cm2/Vs). The improvement was attributed to the good charge newlinecarrier delocalization, high degree of protonation, and good orientation of tubular newlinestructures. The thermoelectric results showed that PPy tube exhibited significantly newlinehigher electrical conductivity (185.7 S/m at 370 K), 244 times larger