This work presents a systematic assessment of electrochemical responses of n-type bismuth telluride-based thermoelectric materials in NaCl solutions. A single-phase alloy and a nanocomposite (with embedded MoS2 nanoparticles) produced by means of mechanical alloying and hot extrusion were investigated. The polarization and electrochemical impedance spectroscopy tests in NaCl solutions revealed that the passivity of the nanocomposite specimen was considerably improved compared with the coarse-grained single-phase alloy. Mott–Schottky analysis revealed that passive layers of both single-phase alloy and nanocomposite specimens had an n-type semiconducting behavior, and the donor density reduced in the passive layer of the nanocomposite specimen.
