Enhanced thermoelectric properties of Nb-doped SrTiO3 polycrystalline ceramic by titanate nanotube addition

The effects of titanate nanotube (TNT) addition on the thermoelectric properties of Nb-doped SrTiO3 polycrystalline ceramic are discussed. Nb-doped SrTiO3 ceramic composite with TNT addition was fabricated by the pressure-less sintering method in an Ar atmosphere. TNT addition significantly enhanced the ratio of the electrical conductivity to thermal conductivity. Meanwhile, the Seebeck coefficient was almost independent of TNT addition, thus, enhancing the dimensionless thermoelectric figure of merit (ZT-value). The sample with TNT addition (2 vol%) gave the maximum ZT-value of 0.14 at 900 K. The reason for the enhanced thermoelectric properties by TNT addition was also investigated.