Thermal and electrical characterization of nanocomposites for thermoelectrics

Abstract

Nanostructures have been shown theoretically, and to a certain extent experimentally, to exhibit enhanced thermoelectric properties. While the use of thermoelectric devices is not widespread today, even marginal improvements in performance could lead to a revolution in small-scale energy conversion and generation and heat removal applications. The potential integration of nanostructures into actual thermoelectric devices has not been fully realized since these devices generally require larger scale materials for the thermoelectric elements. Therefore, a focused investigation into thermal, electrical and thermoelectric characteristics of nanocomposites comprised of nanostructures that, in their bulk form, exhibit good thermoelectric characteristics, was conducted. The presented research explores the thermal and electrical properties of nanocomposites comprised of bismuth nanoparticles that were embedded in a conducting polymer matrix. The thermal and electrical conductivities as well as the thermopower of thin films of polyaniline (the conducting polymer) with different volume fractions of nanoparticles were measured. Results demonstrate that the thermal and electrical properties of polyaniline may be significantly influenced by the presence of the nanoparticles.

A Review on Electroactive Polymers for Waste Heat Recovery

“…The Peltier effect occurs when a current flow through a conducting material results in heat generation or cooling [45,46,47]. These thermoelectric effects occur as a result of the interdependent processes of electric charge and heat transport [46,47,48]. The theoretical efficiency of the thermoelectric materials and devices is given by Equation (1): $\eta =\left(\frac{T_H-T_C}{T_H}\right)\frac{(\sqrt{1+ZT}-1}{(\sqrt{1+ZT}-(T_C/T_H\left)\right)}$ where T H (K) is the hot side temperature, T C (K) is the cold side temperature, and ZT is the thermoelectric figure of merit.…”

“…The dimensionless thermoelectric figure of merit ZT is given by Equation (2): $ZT=\frac{{\alpha }^2\sigma T}{k}=\frac{{\alpha }^{2}T}{\rho k}$ where α (V/K) is the Seebeck coefficient (also known as the thermopower), σ (S/m) is the electrical conductivity, ρ (Ω∙m) is the electric resistivity, k [W/m∙K] is the thermal conductivity, and T (K) is the absolute temperature [48,49]. The figure of merit in the form of Z (K −1 ) can be also found in the literature [50,51].…”

“…Synthesis of such a material is still a challenge, due to an inconvenient coupling of the Seebeck coefficient with thermal and electrical conductivity limiting the value of ZT and thermoelectric efficiency [48,50]. …”

“…either semimetals (e.g., selenium and aluminum) and their oxides or alloys, as the non-metallic modifiers sulfuric and carbon fillers (e.g., nanotubes, graphene, carbon black and graphite) can be applied [99]. A number of studies show the possibility of polyaniline modification by different thermoelectrically active materials, e.g., bismuth telluride [67], bismuth [48], and scutterudite [96]. …”

Synthesis, Characterization and Electrical Properties of a Composite of Topological Insulating Material: Bi2Te3-PANI

“…Various research workers have attempted to synthesize and characterize composites of Bi 2 Te 3 with polyaniline Xu et al, 2005;Hostler et al, 2006;Chatterjee et al, 2009;Toshima et al, 2011).…”