Fabrication and thermoelectric properties of perovskite-type oxide La1−xSrxCoO3 (x = 0, 0.1)

P-type perovskite oxides La1−xSrxCoO3 (x = 0, 0.1) have been prepared by solid state reactions and sol–gel processes. The Seebeck coefficient, electrical conductivity and thermal conductivity of the samples have been investigated. It is found that substitution of Sr for La significantly improved the electrical conductivity but reduced the Seebeck coefficients and thermal conductivity. The samples with the same composition prepared from different routes distinguished from each other in morphologies but exhibited similar conductive mechanism and had the same energy gap Eg and motional enthalpy ΔHm. The effects of density on electrical and thermal conductivity were obvious. The room-temperature ZT value of the sol–gel derived La0.9Sr0.1CoO3 was 0.046, which is comparable to that of the single crystal NaCo2O4 (ZT = 0.03).