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Abstract At present, the weak thermoelectric and mechanical performance of zone‐melting bismuth telluride alloys cannot support the further improvement of cooling and processing performance of semiconductor refrigeration devices. Here, MnO 2 is added into high‐strength Bi 0.4 Sb 1.6 Te 3 prepared by ball milling method to optimize its thermoelectric transport properties. Via in situ reaction, Sb 2 O 3 nano‐precipitates are formed in the matrix, which also leads to the surplus of Te element. As results, the donor‐like effect is suppressed, thereby increasing carrier concentration and power factor. Besides, volatilization of Te‐rich phases during sintering leaves plentiful nanopores, which together with Sb 2 O 3 nano‐precipitates significantly decrease the lattice thermal conductivity. Eventually, the maximum ZT reaches 1.43 at 75 °C for the Bi 0.4 Sb 1.6 Te 3 +0.01MnO 2 sample. On this basis, a 31‐pairs module made of the material and commercial n‐type BiTeSe produces large temperature differences (Δ T ) of 70.1, 80.8, and 89.4 K at the hot‐side temperature ( T h ) of 300, 325, and 350 K respectively, which are highly competitive. The maximum coefficient of performance of 8.6 and cooling capacity of 7 W are achieved when T h is set as 325 K. This excellent progress will promote the further development of bismuth telluride refrigeration modules.
Sun et al. (Sat,) studied this question.