High Performance Thermoelectric Power of Bi_0.5Sb_1.5Te₃Through Synergistic Cu₂GeSe₃and Se Incorporations

Abstract

Bi2Te3‐based alloys are the benchmark for commercial thermoelectric (TE) materials, the widespread demand for low‐grade waste heat recovery and solid‐state refrigeration makes it imperative to enhance the figure‐of‐merits. In this study, high‐performance Bi0.5Sb1.5Te3 (BST) is realized by incorporating Cu2GeSe3 and Se. Concretely, the diffusion of Cu and Ge atoms optimizes the hole concentration and raises the density‐of‐states effective mass (md*), compensating for the loss of “donor‐like effect” exacerbated by ball milling. The subsequent Se addition further increases md*, enabling a total 28% improvement of room‐temperature power factor (S2σ), reaching 43.6 µW cm−1 K−2 compared to the matrix. Simultaneously, the lattice thermal conductivity is also significantly suppressed by multiscale scattering sources represented by Cu‐rich nanoparticles and dislocation arrays. The synergistic effects yield a peak ZT of 1.41 at 350 K and an average ZT of 1.23 (300–500 K) in the Bi0.5Sb1.5Te2.94Se0.06 + 0.11 wt.% Cu2GeSe3 sample. More importantly, the integrated 17‐pair TE module achieves a conversion efficiency of 6.4%, 80% higher than the commercial one at ΔT = 200 K. These results validate that the facile composition optimization of the BST/Cu2GeSe3/Se is a promising strategy to improve the application of BST‐based TE modules.

Leveraging the Cu2SnTe3 additive for an improved thermoelectric figure of merit and module efficiency in Bi0.5Sb1.5Te3-based composites

“…As summarized in Fig. 5c and d, in comparison to the results of high-performance p-type Bi 2 Te 3 -based materials containing Cu, prepared through complex processes, as reported by other researchers, including (Bi,Sb) 2 Te 3 /Cyclic SPS, 59 (Bi,Sb) 2 Te 3 /Two-step sintering, 60 (Bi,Sb) 2 Te 3 /Melt-centrifugation, 61 (Bi,Sb) 2 Te 3 /CuPc, 32 (Bi,Sb) 2 Te 3 /Cu 2 Te, 53 (Bi,Sb) 2 Te 3 /CuO, 51 and so forth, 19,52,54 the top values are highly competitive, and the ZT ave value also surpasses most values known to us. 19,32,51–54,60 In addition, engineering ZT ( ZT eng ) can be used to evaluate the maximum thermoelectric conversion efficiency ( η max ).…”

“…6f provides a summary of the η max at different values of Δ T , and literature data from other Bi 2 Te 3 -based modules are also included for comparison. 7,19,20,23,49,52,59 Overall, the heat-to-electricity conversion efficiency reaches as high as ∼6.0% at Δ T = 200 K, representing a significant increase of nearly 71.4% compared to the 3.5% value in commercial modules. Moreover, it surpasses that of most recently reported Bi 2 Te 3 -based modules, nearly notable in the whole temperature interval of 50–200 K.…”

“…17 Initiating from the perspective of enhancing phonon scattering to reduce κ ph , particularly for polycrystalline materials of p-type Bi x Sb 2− x Te 3 , various processing techniques have been developed to improve ZT and mechanical properties. Such strategies encompass “top-down” processing techniques {such as ball milling (BM), 18,19 melt spinning combined with hot pressing or spark plasma sintering (SPS) 20,21 }, excess liquid Te-assisted sintering for dislocation defect engineering, 22 control of porosity, 23 manipulating the twin boundary, 24 and encapsulated bilayer defects, 25 among others, resulting in an increase in the ZT value to above 1.…”

All-Inorganic Halide Perovskites Boost High-Ranged Figure-of-Merit in Bi0.4Sb1.6Te3 for Thermoelectric Cooling and Low-Grade Heat Recovery

“…The microscopic appearance of indentation with 0.4903 N test force of (e) pristine BST and (f) 0.75 mol % CsPbI 3 /BST samples. (g) Comparison of pristine BST and CsPbI 3 -based composites, together with high performance BST material with excellent hardness. ,,, (h) Raman spectra of pristine and CsPbI 3 composite samples. (i) Williamson–Hall analysis for lattice strain through XRD peak broadening.…”

“…(e) Comparison of this work and materials with top ZT values prepared by other strategies in BST system. ,,,− (f) Cooling performance of 0.50 mol % CsPbI 3 /BST with commercial Bi 2 Te 2.7 Se 0.3 (BTS) n -type leg under different working current. (g) Conversion efficiency as a function of temperature difference for CsPbI 3 /BST-Mg 3 Sb 0.8 Bi 1.2 integrated module compared with that of reported high-performance TEG. ,,− …”