Effect of Graphene Oxide and Carbon Black on the Thermoelectric Performance of Niobium doped Strontium Titanate

Yibing Zhu, Dursun Ekren, Jianyun Cao, Xiaodong Liu, Stephanie r Mudd, Rebecca Boston, Xiuqi Xia, Yi Li, Ian a Kinloch, David j Lewis, Robert Freer

Research output: Contribution to journalArticlepeer-review

Abstract

Strontium titanate-based ceramics are promising n-type thermoelectrics due to their low cost and high thermal and chemical stability. Here, SrTi0.85Nb0.15O3 was prepared with carbon additions of electrochemically produced graphene oxide (eGO) and commercially available carbon black (CB). Ceramic samples were sintered at 1700 K under a reducing atmosphere. XRD, HR-TEM and Raman spectra confirmed the matrix phase was cubic perovskite; there were no carbon residues. By incorporating graphene oxide, the electrical conductivity increased nine-fold to 2818 S cm-1 at 300 K as a result of enhanced carrier mobility. In contrast, the carbon black samples exhibited low density and a small average grain size of ~1 μm. High-resolution X-ray photoelectron spectroscopy revealed the presence of a large number of ionised impurities in the carbon black samples, which significantly enhanced scattering effects; low thermal conductivities of 1.7 W m-1 K-1 were achieved at 873 K. The work reveals that eGO promotes charge transport in SrTiO3, while CB significantly suppresses phonon transport. Both effects are relevant to the development of other thermoelectrics.
Original languageEnglish
Article number174242
JournalJournal of Alloys and Compounds
Volume988
Early online date24 Mar 2024
DOIs
Publication statusE-pub ahead of print - 24 Mar 2024

Keywords

  • Thermoelectric Oxide
  • Polycrystalline Strontium Titanate
  • Grain Boundary
  • Graphene Oxide
  • Carbon Black

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