Thermoelectric Power Generation Applications Research Articles

Thermally Driven Spin Transport of Epitaxial FeRh Films with a Non-magnetic Pt Layer via the Longitudinal Spin Seebeck Effect.

FeRh has been demonstrated to be an important material for the observation of magnetic phase transitions, such as the first-order transition from an antiferromagnetic (AFM) to a ferromagnetic (FM) state, in response to changes in the temperature. This is because of the magnetic moment induced in Rh atoms above the magnetic phase transition temperature. In the present study, we focus on the longitudinal spin Seebeck effect (LSSE), which involves the generation of spin voltage as a result of a temperature gradient in FM materials or FM insulators, and experimentally assess the effect of the crystalline quality of FeRh films and the properties of the substrate on the LSSE thermopower during the FM-AFM phase transition. The measured LSSE thermopower of an epitaxial (110)-oriented FeRh film grown on an Al2O3 substrate is approximately 60 times higher than that of a polycrystalline FeRh film on a SiO2/Si substrate. This can be explained by the high magnetic sensitivity and superior FM properties of (110)-oriented epitaxial FeRh films. Furthermore, by comparing the transverse thermoelectric voltage for in-plane magnetized (IM) and perpendicularly magnetized (PM) configurations, we quantitively evaluate the contribution of the exclusive anomalous Nernst effect (ANE) to the LSSE signals in the FeRh/Al2O3 structure, finding it to be approximately 15-30% over a temperature range of 75-300 K. LSSE measurements in Pt/FeRh films are thus demonstrated to provide a versatile pathway for the development of thermoelectric power generation applications and other practical spintronics and neuromorphic computing devices.

Enhancing visible light absorption of form-stable CH3COONa·3H2O composite phase change material and its application in thermoelectric power generation

The utilization of Phase Change Material (PCM) for solar heat storage represents an effective solar energy storage method. Nevertheless, this promising technology encounters several obstacles, particularly PCM leakage and dissatisfied solar absorptance. This study focuses on the development of a photothermal conversion composite PCM tailored for solar energy storage and its subsequent integration into a thermoelectric power generation system. The composite PCM was synthesized using an evaporation-impregnation method, with melamine foam (MF) serving as the adsorbent material, graphene oxide (GO) as the light-absorbing component, and sodium acetate trihydrate (SAT) as the thermal storage medium. It is shown that the MF demonstrates an exceptional adsorption capacity for SAT, whose mass fraction exceeds 99 % in the final composite. The composite PCM exhibits a remarkable melting enthalpy of 251.5 J/g, comparable to that of pure SAT. The integration of GO into MF/SAT improves the solar absorptance of the composite, elevating it from 23.3 % to 81.5 %, thereby enhancing the photothermal conversion performance. To assess the practical solar energy storage potential of the prepared PCM, a thermoelectric power generation system was designed and underwent a continuous 22-hour performance test in a real outdoor enviornment. The results reveal that the system is able to maintain voltage generation for about 10 hours after the sun disappears. This proves the superior photothermal conversion and heat storage capabilities of the prepared materials. This research offers a viable approach for direct solar energy storage and conversion to electricity, advancing renewable energy technologies.

Heavy elemental compound addition enhancing thermoelectric performance of Chromium Silicide synthesized by Spark plasma sintering

Silicide-based materials drive great potential in developing mid-temperature range thermoelectric generators (TEGs) applications. However, realizing the efficient and stable silicide materials is still a constraint for its real potential device applications. Chromium silicide will likely become p-type thermoelectric materials in this direction for thermoelectric power generation applications. However, high thermal conductivity values impede the figure-of-merit (zT). The present work adopts the chromium silicide, adding different weight percentages of well-known ZrCoSbSn compounds employing the compaction spark plasma sintering (SPS) technique. By adopting these combinations, the thermal conductivity is significantly reduced by enhanced scattering of heat-carrying phonons by multiple interfaces. Also, the maximum power factor value of ≃ 2.1 × 10−3 W/mK2 is achieved by employing a CrSi2 -ZrCoSbSn compound addition. The enhanced figure-of-merit value (zT) ≃ 0.26 is realized in the temperature at 623 K for the CrSi2-5wt% ZrCoSbSn compound material.

Multiscale Phonon Scattering for Ultra‐Low Thermal Conductivity in Co‐Doped ZrCoBi Half‐Heusler

AbstractZrCoBi‐based half‐Heuslers have great potential in thermoelectric power generation due to their high performance in both n‐ and p‐type constituents. In this work, Te and Ni is adopted as an n‐type co‐dopant to increase the carrier concentration and lower the lattice thermal conductivity of ZrCoBi. By further alloying with Sb at the Bi site, a large number of scattering centers of different scales are introduced, significantly reducing the lattice thermal conductivity to ≈1.2 W m−1 K−1 at 300 K and ≈0.96 W m−1 K−1 at 973 K in ZrCo0.94Ni0.06Bi0.775Te0.075Sb0.15. Consequently, the state‐of‐the‐art figure‐of‐merit zT ≈1.2 is achieved, and the average zT reached ≈0.66, which is higher than all of the reported n‐type ZrCoSb‐based and ZrCoBi‐based half‐Heusler alloys. This work provides an effective pathway for optimizing n‐type ZrCoBi alloys, laying the foundation for their further development and application in thermoelectric power generation.

Emerging pathways in thermoelectric: Chemical bath deposition of magnesium selenide thin films for sustainable energy harvesting

In this study, magnesium Selenide (MgSe) thin films were synthesized on glass substrate using the chemical bath deposition (CBD) method for thermoelectric power generation. After cleaning of glass substrate, selenium powder was dissolved in nitric acid to produce SeO2 and magnesium chloride was then introduced as the source of magnesium. Both SeO2 and MgCl2 were dissolved in 100 ml of dI water and later, these solutions were unified gradually. After that, the cleaned glass substrates were placed in the solution, while keeping the reaction temperature constant at 50o C for the deposition durations of 24, 48, 72, and 96 h. A number of characterization techniques, namely X-ray Diffraction (XRD), Raman spectroscopy and Scanning Electron Microscopy (SEM) were performed for structural and surface analysis of grown thin films. The effect of deposition time duration on the thermoelectric properties was investigated in depth using the Seebeck and Hall systems. It was found that the values of the Seebeck coefficient and power factor obey the increasing trend with maximum values 196.93 μV/K and 21.5 × 10−8 W/mK2 respectively. These observed values are seems to be the highest values for magnesium selenide thin film ever reported in the literature according to the best of our knowledge. Therefore, we have concluded that MgSe thin films supposed to be emerging material for thermoelectric power generation applications.

Hundred-Watt Implantable TEG Module for Large-Scale Exhaust Gas Waste Heat Recovery

In this study, we have designed and developed an implantable thermoelectric generator (TEG) module tailored for large-scale flue gas waste heat recovery. We also have established a test stand to simulate diverse operational conditions, and systematically examined the influence of different operating conditions, including flue gas temperature, flue gas velocity, and cooling water temperature, on the electrical performance of the TEG module. When the flue gas temperature is 139 °C, the flue gas flow rate is 3.4 m/s, and the cooling water temperature is 20 °C, the TEG module operates at its peak performance. It achieves an open-circuit voltage of 856.3 V and an output power of 150.58 W. Furthermore, the TEG module demonstrates a notable power generation capacity of 3.86 kW/m3 and a waste heat recovery capacity of 135.85 kW/m3. The results prove the TEG module as an effective solution for large-scale flue gas waste heat recovery in industrial settings, contributing to sustainable energy practices. This study supports the application of thermoelectric power generation in the industrial sector, offering significant potential for advancements in energy efficiency.

Efficient radiative cooling with bi-rhombic metamaterial and its application in thermoelectric power generation

In this work, we have not only demonstrated a bi-rhombic radiative cooling metamaterial but also explored its application in power generation. It exhibits ultrahigh broadband emission in both the first and second atmospheric windows. The net cooling power reaches up to a value of 165.09 W/m2 in the daytime. Based on the analysis of the electric field distribution, such high emissivity in the atmospheric window derives from the patterned metamaterial and the inclusion of the dielectric layer. Moreover, excellent cooling performance is maintained at different incident angles and heat transfer coefficients. The cold end of the thermoelectric generator is coupled to the radiative cooler, which allows for a maximum temperature difference of 8.28 K during the daytime, resulting in continuous and stable power generation. Therefore, the design of bi-rhombic radiative cooling metamaterial provides a simple, economical, and environmentally friendly method to achieve efficient cooling and continuous power generation, thereby enhancing the efficiency of energy utilization.

Photothermal and thermoelectric performance of PCMs doped with nanoparticles and metal foam

Combination of solar thermal power generation and Phase Change Materials (PCMs) helps solve the disadvantages of solar instability. In order to improve the photothermal performance of PCMs, PCMs doped with high thermal conductivity metal foam and nanoparticles were applied. The influence of nanoparticle mass fractions (ω = 0%, 0.5%, 0.8%, 1.0%), pore densities of metal foam (PPI = 5, 10, 15), light intensities (I = 600–1000 mw/cm2) was discussed. Results showed that an increase in pore densities of metal foam is beneficial to improving the thermal conductivity and increasing the temperature difference, the metal foam PPI = 15 can bring a maximum temperature rise of 7.9%, and can increase the temperature difference growth rate by 24.82%. The addition of nanoparticles increases the maximum voltage and power by up to 8.53% and 8.0%, respectively. This research has certain reference and guiding value for the application of thermoelectric power generation.

Controlled growth of Ag-ZnO thin films by thermal evaporation technique for optimized thermoelectric power generation

This manuscript is described the facile and cost-effective growth of silver Zinc Oxide (Ag-ZnO) thin films by simple thermal evaporation method for thermoelectric power generation applications. Growth of samples is started by making pellets of pure silver (Ag) and zinc (Zn) powders which are composed of 1:1 ration and evaporated in vacuum tube furnace. The other growth parameters are fixed as; evaporation time (45 min), evaporation temperature (1010 0C) and oxygen flow rate (60 sccm). Five samples are prepared at different source to substrate distances (6.5–8.5 in.) and post deposition annealing of all samples is carried out at 800 °C using semi-programable muffle furnace. Prepared thin films are analyzed using X-Ray Diffraction (XRD), Raman spectroscopy, Scanning Electron Microscope (SEM) and Seebeck measurements to study the impact of various source to substrate distances on the structural morphological and thermoelectric behavior of Ag-ZnO nanocomposite thin films. The obtained results are revealed that different source to substrate distances strongly influence the structural, morphological, and thermoelectric behavior of prepared thin films. Optimal values for electrical conductivity, Seebeck coefficient and powerful factor of synthesized thin films are calculated as 3.05 × 103 S/m, 645 µV/°C and 1.27 × 10−3 Wm−1 oC−2 respectively at source to substrate distance of 7.0 in.

Growth and characterization of GeSnO thin films for thermoelectric power generation applications

In this paper, we have demonstrated the thermoelectric properties of GeSnO thin films grown by physical vapor deposition technique. The GeSn pellets were prepared by mixing of germanium (Ge) and tin (Sn) powders with 1:1 ratio using a hydraulic press. Hard pellet was evaporated in a vacuum tube furnace on glass substrate. The grown sample was cut into pieces and subjected to the annealing process at different temperatures ranging from 350 to 500 0C in an oxygen environment. XRD data confirmed the formation of GeSnO crystal structure and it was found to be improved up to annealing temperature 350 °C due to the compensation of oxygen vacancy type defects. But further annealing temperature degrades the crystal quality because oxygen atoms get additional thermal energy and it may generate interstitial defects. Raman and SEM data further supported our argument. Seebeck data confirmed the enhancement in the values of Seebeck coefficient, power factor and electrical conductivity with annealing temperature. The enhancement of thermo power with annealing temperature is due the fact that it degrades the crystal quality which resulted in the generation of secondary phases. These secondary phases are the major contributors of Seebeck coefficient and electrical conductivity.

High thermoelectric properties realized in earth abundant Bi2S3 bulk materials via Se and Cl co-doping in solution synthesis process

• Se and Cl co-doped nanostructured Bi 2 S 3 powders were successfully synthesized via hydrothermal. • A high σ value of 483 S cm −1 is obtained at 300 K for the Bi 2 S 2.4 Se 0.4 Cl 0.20 sample. • A high PFave. of 411 μW m −1 K −2 is achieved for the Bi 2 S 2.4 Se 0.4 Cl 0.20 . • The highest ZT value of 0.66 is achieved at 673 K for the Bi 2 S 2.4 Se 0.4 Cl 0.20 sample. Bi 2 S 3 -based alloys are considered promising thermoelectric materials due to their large Seebeck coefficient and low lattice thermal conductivity. However, low electrical conductivity usually leads to poor electrical transport properties, which seriously restricts their further application in thermoelectric refrigeration and/or power generation. In this work, Bi 2 S 3 with high electrical transport properties is synthesized hydrothermally via Se and Cl co-doping. The maximum electrical conductivity value of 483 S cm −1 was obtained for the Bi 2 S 2.4 Se 0.4 Cl 0.20 sample at room temperature. The significant improvement of electrical conductivity gives rise to a high average power factor of 411 μW m −1 K −2 during the measuring temperature range and a peak value of 456 μW m −1 K −2 at 673 K. Benefiting from the largely improved electrical transport properties, a superior ZT value of approximately 0.66 and ZT ave . of 0.36 were obtained for Bi 2 S 2.4 Se 0.4 Cl 0.20 , and the theoretically calculated conversion efficiency reached 5.7%. The results indicate that Bi 2 S 3 is a promising candidate for thermoelectric applications at medium temperatures. A high ZT value in Bi2S3 system of ∼0.66 was achieved at 673 K for Bi2S3 with Se and Cl co-doped through a facile hydrothermal followed by spark plasma sintering.

Growth and characterization of Ag–Al2O3 composites thin films for thermoelectric power generation applications

Thin films of Ag–Al 2 O 3 composites were successfully grown on Si substrate by thermal evaporation method and their thermoelectric performance was modulated using post growth annealing technique. Pellet of Ag and Al mixture having 1:4 ratio was evaporated on Si substrate using the vacuum tube furnace. As grown sample was cut into pieces and post-growth annealing was performed at different temperatures using muffle furnace. XRD results suggested that as-deposited sample has amorphous nature, but crystallinity of the samples increase as an annealing temperature increase from 600 to 900 o C. This structural behavior of annealed samples was further verified by Raman spectroscopy measurements. We have reported an optimal annealing temperature (800 0 C) for the best thermoelectric performance of investigated composites. At this specific annealing temperature, charge carriers are highly mobile which resulted in the enhancement of thermoelectric power generation performance of Ag–Al 2 O 3 composite. The value of power factor (1.38x10 −2 W/m-K −2 ) reported in the current study is the highest value for Ag–Al 2 O 3 composites so for reported in the literature according to the best of our knowledge.

Ternary Ag2Se1-xTex: A Near-Room-Temperature Thermoelectric Material with a Potentially High Figure of Merit.

Discovering high-performance near-room-temperature thermoelectric materials is extremely imperative to widen the practical application in thermoelectric power generation and refrigeration. Here, ternary Ag2Se1-xTex (x = 0.1, 0.2, 0.3, 0.4, and 0.5) materials are prepared via the wet-mechanical alloying and spark plasma sintering process to investigate their near-room-temperature thermoelectric properties. From density functional theory calculation and single-parabolic-band modeling study, we found that the reduced contribution of Se 4p orbitals to the total density of states decreases the carrier effective mass with increasing Te content, which should enhance the theoretically maximum zT. These calculation results are also verified by the experimental results. Meanwhile, complex microstructures including dislocations, nanograins, high-density boundaries, TeSe substitution, lattice distortions, and localized strain have been observed in ternary Ag2Se1-xTex. These complex microstructures strengthen phonon scattering and in turn lead to ultralow lattice thermal conductivity in the range of 0.21-0.31 W m-1 K-1 in ternary Ag2Se1-xTex at 300 K. Although the increased deformation potential suppresses the carrier mobility, benefiting from the engineered band structures and ultralow lattice thermal conductivity, a high zT of >1 can be potentially obtained in the ternary Ag2Se1-xTex with appropriate carrier concentration. This study indicates that ternary Ag2Se1-xTex is a promising candidate for near-room-temperature thermoelectric applications.

High Performance of Post-Treated PEDOT:PSS Thin Films for Thermoelectric Power Generation Applications.

Thermoelectric materials capable of converting waste heat energy into electrical energy are enchanting for applications in wearable electronics and sensors by harvesting heat energy of the human body. Organic conducting polymers offer promise of thermoelectric materials for next-generation power sources of wearable devices due to their low cost in preparation, easy processing, low toxicity, low thermal conductivity, mechanical flexibility, light weight, and large area application. Generally, the pristine PEDOT:PSS film has low electrical conductivity, small Seebeck coefficient, and low thermal conductivity. The thermoelectric power factors of conducting polymers of p-type PEDOT:PSS films are considerably improved via synergistic effect by using ethylene glycol and reductants of EG/NaBH4 or EG/NaHCO3. As such, the charge carrier concentration of PEDOT:PSS films is tuned. The synergistic effect might lead to enhanced variation of density of states at the Fermi level and hence enhanced Seebeck coefficient. The resulting PEDOT:PSS films were characterized by atomic force microscopy (AFM), Raman spectroscopy, and XPS spectroscopy. The electrical conductivity and Seebeck coefficient were measured between 325 and 450 K. The carrier concentration and mobility were obtained by Hall measurements. The pristine thin film treated with 0.05 M EG/NaHCO3 solution exhibits the highest power factor of 183 μW m-1 K-2 at 450 K among these two series of films due to its significant enhanced Seebeck coefficient of 48 μV/K. The maximum output power of 121.08 nW is attained at the output voltage of 6.98 mV and the output current of 17.45 μA. The corresponding maximum power density is 98 μW/cm2 for a power generation device made of four pairs of p-leg (EG/NaHCO3 post-treated PEDOT:PSS) and n-leg (Cu0.6Ni0.4) on the polyamide substrate with the size of 4 mm × 20 mm for each leg.

Se-induced enhancement of the high-temperature thermoelectric performance of n-type Cu0.008Bi2(Te,Se)3 alloys due to suppressed bipolar conduction

Bipolar conduction in Bi-Te-based alloys is a critical barrier to high conversion efficiency in thermoelectric power generation applications. Herein, we investigate the effect of Te/Se ratio control on bipolar conduction in n-type Cu0.008Bi2(Te,Se)3. Based on the two-band model and Callaway model, we found that electronic and thermal transports of minority carriers (holes) were gradually decreased with an increase in Se content. The high-temperature power factor of Se-rich Cu0.008Bi2Te2.1Se0.9 was higher in value compared to reference Cu0.008Bi2Te2.7Se0.3 due to the weighted mobility ratio increase, and its bipolar thermal conductivity was significantly reduced simultaneously. As a result, a peak figure of merit (zT) of 0.92 was obtained at 440 K in Cu0.008Bi2Te2.1Se0.9.

Se-Induced Enhancement of the High-Temperature Thermoelectric Performance of <i>n</i>-type Cu <sub>0.008</sub>Bi <sub>2</sub>(Te,Se) <sub>3</sub> Alloys Due to Suppressed Bipolar Conduction

Bipolar conduction in Bi-Te-based alloys is a critical barrier to high conversion efficiency in thermoelectric power generation applications. Herein, we investigate the effect of compositional tuning of Te/Se ratio on bipolar conduction in n-type Cu0.008Bi2(Te,Se)3 alloys. Based on the two-band model and Callaway model, we found that electronic and thermal transports of minority carriers (holes) were gradually decreased with an increase in Se content. The high-temperature power factor of Se-rich Cu0.008Bi2Te2.1Se0.9 was higher in value compared to reference Cu0.008Bi2Te2.7Se0.3 due to the weighted mobility ratio increase, and its bipolar thermal conductivity was significantly reduced simultaneously. As a result, a peak figure of merit (zT) of 0.92 was obtained at 440 K in Cu0.008Bi2Te2.1Se0.9.

A highly efficient organic solar energy-absorbing material based on phthalocyanine derivative for integrated water evaporation and thermoelectric power generation application

The 4OCSPC solid has a wide absorption range from 300 to 1000 nm and the solar-thermal conversion efficiency is evaluated to be 17.3%, which can attain superior water purification and electricity generation performances.

A Facile Synthesis Method of BiSb Nanoparticles for Thermoelectric Applications

BiSb nanoparticles were synthesized by solvothermal method. The synthesized material having a trigonal structure with space group R3m was confirmed through X-ray diffraction pattern. The Williamson-Hall method was employed to analyze the lattice stress and micro-strain produced in the BiSb nanoparticles. On the prepared material surface morphology studies were carried out using HR-SEM with EDXA. UV-visible absorption spectrum shows a wide absorption peak at 287 nm and the estimated band gap value is at Eg = 1.6 eV (from Tauc plot). The values of remanent polarization Pr = 0.156 μC/cm2, saturation polarization Ps = 0.253 μC/cm2, and coercive electric field Ec = 13.5 kV/cm obtained from the loop were close to the value. The BiSb nanoparticles exhibit semi-metallic-reported characteristics. This material is useful for thermoelectric power generation applications.

Effect of annealing temperature on the thermoelectric properties of ZnInO thin films grown by physical vapor deposition

This research work has been demonstrated the growth of ZnInO thin films using thermal evaporation technique for thermoelectric power generation applications. The pure zinc powder and indium metal were evaporated on the multi-crystalline Si substrate using the vacuum tube furnace. Deposited thin films were annealed at various temperatures (500–700 °C) for 30 min in a programmable muffle furnace. XRD data concluded that the sample annealed at temperature 500 °C, has a weak structure of ZnO. But as we have increased the annealing temperature, indium atoms get thermal energy from the annealing process and reacted with ZnO molecule to form ZnInO composite. The vibrational and rotational modes of the samples were studied by the Raman spectroscopic analysis and morphology of annealed samples was verified by SEM. The Seebeck coefficient data suggested that the value of Seebeck coefficient varies between (140.9–182.2) μV/oC. The maximum value of the Seebeck coefficient was obtained for the sample annealed at 600 °C because the mobility of carriers is highest at that temperature. But the value of electrical conductivity and power factor for the sample annealed at 600 °C is minimum due to low carrier concentration. Because of these conclusions, it may be suggested that this material can be a potential choice soon for thermoelectric power generation applications.

Thermal analysis of hydrothermally synthesized nanostructured bismuth telluride semiconductor

Abstract Present research work is focused on thermal analysis of bismuth telluride nanostructure for the evaluation of material properties such as oxidation, recrystallization, thermal stability, melting point etc. From the literature, Bi2Te3 is the most promising material for thermoelectric power generation and refrigeration application. Nanostructured Bismuth telluride is prepared via hydrothermal method at various hot air oven conditions. Synthesized material is characterized through XRD, SEM, TEM, AFM and FESEM. XRD results are showed the maximum intensity peak at 27.6° with (015) preferred plane. SEM results shows the formation of nanoflower and nanorods at 155 ℃ and 210 ℃ respectively. Next, DSC, DTA and TGA analysis from RT to 812 ℃ are carried out in N2 and Air environment. Only one peak at 521 ℃ is found in DSC curve indicating that phase transition or crystallization of the material and mass loss is 0.234 mg/min. When we did the DSC, DTA and DTG in air environment, we found the three peaks at 384 ℃, 461 ℃, and 509 ℃. First peak indicates oxidation due to the presence of moisture in sample and other two peaks shows the phase transition of the material. Material is decomposed at 511℃ as observed in TG curve.