Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and hi...Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and high electrical conductivity,polycrystalline SrTiO_(3)with a multi-scale architecture was designed by the co-doping with lanthanum,cerium,and niobium.High-quality nano-powders were synthesized via a hydrothermal method.Nano-inclusions and a nano/micro-sized second phase precipitated during sintering to form mosaic crystal-like and epitaxial-like structures,which decreased the thermal conductivity.Substituting trivalent Ce and/or La with divalent Sr and substituting pentavalent Nb with tetravalent Ti enhanced the electrical conductivity without decreasing the Seebeck coefficient.By optimizing the dopant type and ratio,a low thermal conductivity of 2.77 W·m^(-1)·K^(-1)and high PF of 1.1 mW·m^(-1)·K^(-2)at 1000 K were obtained in the sample co-doped with 5-mol%La,5-mol%Ce,and 5-mol%Nb,which induced a large ZT of 0.38 at 1000 K.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51702168 and 51532006).
文摘Strontium titanate(SrTiO_(3))is a thermoelectric material with large Seebeck coefficient that has potential applications in high-temperature power generators.To simultaneously achieve a low thermal conductivity and high electrical conductivity,polycrystalline SrTiO_(3)with a multi-scale architecture was designed by the co-doping with lanthanum,cerium,and niobium.High-quality nano-powders were synthesized via a hydrothermal method.Nano-inclusions and a nano/micro-sized second phase precipitated during sintering to form mosaic crystal-like and epitaxial-like structures,which decreased the thermal conductivity.Substituting trivalent Ce and/or La with divalent Sr and substituting pentavalent Nb with tetravalent Ti enhanced the electrical conductivity without decreasing the Seebeck coefficient.By optimizing the dopant type and ratio,a low thermal conductivity of 2.77 W·m^(-1)·K^(-1)and high PF of 1.1 mW·m^(-1)·K^(-2)at 1000 K were obtained in the sample co-doped with 5-mol%La,5-mol%Ce,and 5-mol%Nb,which induced a large ZT of 0.38 at 1000 K.
