Thermoelectric properties of BiBO3-added Bi2Sr2Co2Oy ceramics

The thermoelectric properties of BiBO3-added Bi(2)Sr(2)Co(2)Oyceramics have been investigated. Bi(2)Sr(2)Co(2)Oy+ x wt % BiBO(3)materials (x = 0, 0.16, 0.50, and 0.80) were prepared by the sol-gel method. The values of power factor (PF) and figure of merit (ZT) were evaluated using electrical resistivity (mu), Seebeck coefficient (S) and thermal conductivity (k) measurements. The Bi(2)Sr(2)Co(2)Oy+ 0.16 wt % BiBO(3)sample has the lowest mu among all studied materials. The S rises with a rising temperature above 400 K, indicating p-type conductivity for each sample. The value of S for the reference (pristine) Bi(2)Sr(2)Co(2)Oyat 973 K is approximately 3-10 % higher than the BiBO3-added compositions. Reference and 0.16 wt % BiBO3-added samples exhibit higher PF values than those with higher BiBO(3)content (x = 0.50 and 0.80). Adding bismuth borate (x> 0.16) leads to a 1.6-fold decrease in the thermal conductivity of the Bi(2)Sr(2)Co(2)Oysystem at 573 K. The decrease of mu (x = 0.16) and k (for all BiBO(3)added compositions) resulted in a 39 % improvement in the ZT value.