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

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 center dot 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 mu VK-1.