N-Type Bismuth Telluride Nanocomposite Materials Optimization for Thermoelectric Generators in Wearable Applications

Abstract

Thermoelectric materials could play a crucial role in the future of wearable electronic devices. They can continuously generate electricity from body heat. For efficient operation in wearable systems, in addition to a high thermoelectric figure of merit, zT, the thermoelectric material must have low thermal conductivity and a high Seebeck coefficient. In this study, we successfully synthesized high-performance nanocomposites of n-type Bi2Te2.7Se0.3, optimized especially for body heat harvesting and power generation applications. Different techniques such as dopant optimization, glass inclusion, microwave radiation in a single mode microwave cavity, and sintering conditions were used to optimize the temperature-dependent thermoelectric properties of Bi2Te2.7Se0.3. The effects of these techniques were studied and compared with each other. A room temperature thermal conductivity as low as 0.65 W/mK and high Seebeck coefficient of −297 μV/K were obtained for a wearable application, while maintaining a high thermoelectric figure of merit, zT, of 0.87 and an average zT of 0.82 over the entire temperature range of 25 °C to 225 °C, which makes the material appropriate for a variety of power generation applications.

A review on recent developments of thermoelectric materials for room-temperature applications

“…The authors revealed that at 300K, the highest value of 0.14 was achieved by the synthesized sample at 1Gpa pressure. Nozariasbmarz et al [50] tried to improve the TE properties of bulk nanostructured n-type Bi2Te2.7Se0.3 materials using different techniques, including dopant addition, tellurium vacancies, glass inclusion, spark plasma sintering time and temperature, microwave processing, and subsequent annealing. The experiments were focused on optimizing the materials' properties concerning wearable TEGs.…”

Bismuth Telluride Thermoelectrics with 8% Module Efficiency for Waste Heat Recovery Application

“…The (zT) peak of Type (I)-n and Type (II)-n is 0.92 and 0.9, respectively. In Type (II)-n, zT~0.9 is maintained in a broad temperature range from 50 C to -n has lower thermal conductivity and higher Seebeck coefficient and zT at room temperature, which makes this material appropriate for applications that require large contact resistance between TE and heat source/sink at room temperature such as wearable electronics (Nozariasbmarz et al, 2019a(Nozariasbmarz et al, , 2019b2020a, 2020b. However, comparatively Type (I)-n is not the best candidate for power generation at high temperature due to its zT degradation.…”

Unraveling energy consumption by using low-cost and reevaluated thermoelectricThin Films

“…These are often connected thermally in parallel and electrically in series, demonstrating the efficiency and enhancing diversity for applications. In this study, thin films of Antimony (Sb) were chosen as an p-type material, and Selenium (Se) was chosen as a n-type material [12,13]. Figure 3 represents the X-ray diffraction (XRD) patterns of BiTeSb and BiTeSe thin films on various substrates at room temperature.…”

“…In general, commercial thermoelectric devices are produced from sintered bulk materials. However, these bulk materials have a low figure of merit (ZT) due to both their electrical conductivity and low Seebeck coefficients [2,9,13]. To increase thermoelectric properties, low-dimensional interactions are used to boost the density of states (DOS) in the vicinity of the Fermi level, enhancing phonon scattering on nanostructured materials and giving a lead to increase charge carrier mobility [10] and thin film nanotechnology allows for the probability of decorating the devices to micro-or nanodimensions and for easy coordination with the standard applications with different substrate options.…”