Precursor-Led Grain Boundary Engineering for Superior Thermoelectric Performance in Niobium Strontium Titanate

Yibing Zhu, Feridoon Azough, Xiaodong Liu, Xiangli Zhong, Minghao Zhao, Kalliope Margaronis, Sohini Kar-Narayan, Ian Kinloch, David J. Lewis, Robert Freer

Research output: Contribution to journalArticlepeer-review


We present a novel method to significantly enhance the thermoelectric performance of ceramics in the model system SrTi0.85Nb0.15O3 through the use of the precursor ammonium tetrathiomolybdate (0.5–2% w/w additions). After sintering the precursor-infused green body at 1700 K for 24 h in 5% H2/Ar, single-crystal-like electron transport behavior developed with electrical conductivity reaching ∼3000 S/cm at ∼300 K, almost a magnitude higher than that in the control sample. During processing, the precursor transformed into MoS2, then into MoOx, and finally into Mo particles. This limited grain growth promoted secondary phase generation but importantly helped to reduce the grain boundary barriers. Samples prepared with additions of the precursor exhibited vastly increased electrical conductivity, without significant impact on Seebeck coefficients giving rise to high power factor values of 1760 μW/mK2 at ∼300 K and a maximum thermoelectric figure-of-merit zT of 0.24 at 823 K. This processing strategy provides a simple method to achieve high charge mobility in polycrystalline titanate and related materials and with the potential to create “phonon-glass-electron-crystal” oxide thermoelectric materials.
Original languageEnglish
Pages (from-to)13097-13107
JournalACS applied materials & interfaces
Issue number10
Early online date28 Feb 2023
Publication statusPublished - 15 Mar 2023


  • MoS
  • ammonium tetrathiomolybdate
  • grain boundary resistance
  • high charge mobility
  • strontium titanate
  • thermoelectric


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