Electrodeposition of Bi–Te Thermoelectric Material in Ethylene Glycol-BiCl₃–TeCl₄ Non-Aqueous Solution

Abstract

The electrodeposition of bismuth–tellurium thermoelectric material was investigated by galvanostatic and potentiostatic electrolysis in ethylene glycol (EG)-BiCl3–TeCl4 non-aqueous solutions at 393 K. Controlling the molar ratio of BiCl3 to TeCl4 in the bath and the electrolysis conditions, the Bi–Te alloys with various compositions were electrodeposited. The composition of the electrodeposit obtained in the 97.50 mol%EG-2.45 mol%BiCl3–0.05 mol%TeCl4 bath with the BiCl3 to TeCl4 molar ratio of 50:1 at the current density of 20 A·m−2 was 40.14 mol%Bi–59.86 mol%Te and close to that of Bi2Te3. This electrodeposit exhibited a n-type thermoelectric conversion for the given temperature difference and its Seebeck coefficient was −145 µV K−1.