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Page 10 of 15 Xie et al. Energy Mater. 2025, 5, 500127 https://dx.doi.org/10.20517/energymater.2025.48

Figure 7. Energy-dispersive X-ray spectroscopy (EDS) mapping of Bi Sb Te spark plasma sintered (SPS) pellet. (A) Top-view SEM
0.5 1.5 3-x
image of the pellet surface, with corresponding elemental distribution maps of (B) tellurium, (C) antimony and (D) bismuth, indicating
a uniform elemental distribution across the surface.

In this study, the thermoelectric properties of melt-spun Bi-Sb-Te compounds with varying compositions
(x = 0.15, x = 0, and x = -0.15) were systematically investigated over a temperature range of 300-480 K. The
primary thermoelectric parameters analyzed include electrical conductivity (σ), the Seebeck coefficient, and
the power factor. Among these, electrical conductivity is a crucial factor, as it directly influences the
efficiency of thermoelectric energy conversion [34,35] . Figure 8A illustrates the temperature-dependent
electrical conductivity of the Bi-Sb-Te samples. For the composition with x = 0.15, the electrical
conductivity at room temperature (300 K) was measured to be 1,046 S·cm . As the temperature increased to
-1
480 K, the conductivity decreased to 739 S·cm . In comparison, the samples with x = 0 and x = -0.15
-1
-1
exhibited lower electrical conductivities at room temperature, measured at 392 and 346 S·cm , respectively.
Across all compositions, electrical conductivity was observed to decrease with increasing temperature, a
behavior consistent with degenerate semiconductor characteristics . These results indicate that carrier
[36]
scattering increases with temperature, leading to a reduction in mobility and, consequently, a decline in
electrical conductivity. The higher σ value observed in the x = 0.15 sample suggests improved carrier
concentration or mobility, potentially due to optimal stoichiometry or microstructural features induced by
the melt spinning process.

A significant enhancement in electrical conductivity was achieved by reducing the Te content in Bi-Sb-Te
compounds. Specifically, the conductivity increased from 392.25 S·cm for Bi Sb Te (x = 0) to
-1
1.5
3-x
0.5
-1
1,046.87 S·cm for Bi Sb Te (x = 0.15). This improvement is primarily attributed to the formation of
3-x
1.5
0.5
antisite defects induced by Te deficiency, which generates a higher hole concentration, as confirmed by Hall
carrier concentration measurements. Among the tested compositions, the x = 0.15 sample consistently