Thermoelectric Properties of Reduced Polycrystalline Sr 0.5 Ba 0.5 Nb 2 O 6 Fabricated Via Solution Combustion Synthesis

The thermoelectric properties of bulk polycrystalline Sr 0.5 Ba 0.5 Nb 2 O 6 ( SBN 50) fabricated via solution combustion synthesis ( SCS ) and reduced at temperatures of 900°C–1150°C were explored. The Seebeck coefficient ( S ) of all samples increased over the entire range of testing temperatures; a peak S value of −281 μV/K was obtained at 930 K for the sample reduced at 900°C. A metal‐insulator transition was observed in the electrical conductivity (σ) of samples reduced at 1000°C–1150°C, whereas only semiconducting electrical behavior was observed for the sample reduced at 900°C. An optimal balance between S and σ was achieved for the pellet reduced at 1000°C, which exhibited a maximum power factor of 1.78 μW/cm·K 2 at 930 K. Over a temperature range of 300–930 K, the thermal conductivity (κ) of as‐processed and reduced (1000°C) SBN 50 was found to be 1.03–1.4 and 1.46–1.84 W/m·K, respectively. A maximum figure of merit ( ZT ) of 0.09 was obtained at 930 K for the 1000°C‐reduced sample. X ‐ray photoelectron spectroscopy revealed that the Nb 2+ peak intensity increased at higher reduction temperatures, which could possibly lead to a distortion of NbO 6 octahedra and a decrease in the Seebeck coefficient.