Enhanced thermoelectric properties of Cu2−δSe nanopowder dispersed Bi2Ba2Co2Oy ceramics

The Bi 2 Ba 2 Co 2 O y ceramics dispersed with x wt% Cu 2−δ Se ( 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 Cu 2−δ Se dispersion on the thermoelectric properties were investigated. The thinner and better aligned lamellar structures were observed in the Cu 2−δ Se dispersed Bi 2 Ba 2 Co 2 O y 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 Cu 2−δ Se dispersion owing to its low electrical resistivity. As a result, all the Cu 2−δ Se dispersed samples exhibited higher figure of merit ( ZT ), indicating that Cu 2−δ Se dispersion is an effective method to raise the thermoelectric properties of Bi 2 Ba 2 Co 2 O y ceramic. The maximum ZT value 0.21 was achieved at 873 K when the Cu 2−δ Se amount is 0.5 wt%, which is increased about 35% compared with the undispersed sample.