Enhanced thermoelectric properties of Cu2−δSe nanopowder dispersed Bi2Ba2Co2Oy ceramics

The Bi2Ba2Co2Oy ceramics dispersed with x wt% Cu2−δSe (x = 0.00, 0.25, 0.50, 0.75, 1.00, 1.25 and 1.50) nanopowders were synthesized by the solid-state reaction method and the effects of Cu2−δSe dispersion on the thermoelectric properties were investigated. The thinner and better aligned lamellar structures were observed in the Cu2−δSe dispersed Bi2Ba2Co2Oy samples, which resulted in the significant reducing of thermal conductivities due to the enhanced phonon scattering by the lamellar structures. At the same time, the electrical resistivity was reduced evidently by an appropriate amount of Cu2−δSe dispersion owing to its low electrical resistivity. As a result, all the Cu2−δSe dispersed samples exhibited higher figure of merit (ZT), indicating that Cu2−δSe dispersion is an effective method to raise the thermoelectric properties of Bi2Ba2Co2Oy ceramic. The maximum ZT value 0.21 was achieved at 873 K when the Cu2−δSe amount is 0.5 wt%, which is increased about 35% compared with the undispersed sample.