Thermoelectric properties of Bi3+ substituted Co-based misfit-layered oxides

Abstract

Highly densified (Ca1−xBix)3Co4O9 thermoelectric ceramics with a layered structure were prepared by a sol–gel method followed by spark plasma sintering (SPS). Thermoelectric (TE) properties of the complex oxide ceramics were measured from room temperature to 700 °C. The results show that Bi3+ substitution leads to an increase in both electrical conductivity and Seebeck coefficient simultaneously. Bi3+ doped samples also show a lower thermal conductivity than undoped samples. The dimensional figure of merit ZT value of (Ca0.95 Bi0.05)3Co4O9 samples is 0.25 at 700 °C.