Spark Plasma Sintering (SPS)-Assisted Synthesis and Thermoelectric Characterization of Magnéli Phase V₆O₁₁

Journal Article · Thu Jan 11 00:00:00 EST 2018 · Inorganic Chemistry

DOI:https://doi.org/10.1021/acs.inorgchem.7b02669· OSTI ID:1436798

Joos, Markus ^[1]; Cerretti, Giacomo ^[1]; Veremchuk, Igor ^[2]; Hofmann, Patrick ^[3]; Frerichs, Hajo ^[1]; Anjum, Dalaver H. ^[4]; Reich, Tobias  ^[1]; Lieberwirth, Ingo ^[5]; Panthöfer, Martin ^[1]; Zeier, Wolfgang G.  ^[3]; Tremel, Wolfgang  ^[1]

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1. Johannes Gutenberg-Univ., Mainz (Germany)
2. Max Planck Inst. for Chemical Physics of Solids, Dresden (Germany)
3. Justus-Liebig-Univ. Gießen, (Germany)
4. King Abdullah Univ. of Science and Technology, Thuwal (Saudi Arabia)
5. Max Planck Inst. for Polymer Research, Mainz (Germany)

The Magnéli phase V6O11 was synthesized in gram amounts from a powder mixture of V₆O₁₁/V₇O₁₃ and vanadium metal, using the spark plasma sintering (SPS) technique. Its structure was determined with synchrotron X-ray powder diffraction data from a phase-pure sample synthesized by conventional solid-state synthesis. A special feature of Magnéli-type oxides is a combination of crystallographic shear and intrinsic disorder that leads to relatively low lattice thermal conductivities. SPS prepared V₆O₁₁ has a relatively low thermal conductivity of κ = 2.72 ± 0.06 W (m K)^–1 while being a n-type conductor with an electrical conductivity of σ = 0.039 ± 0.005 (μΩ m)^–1, a Seebeck coefficient of α = –(35 ± 2) μV K^–1, which leads to a power factor of PF = 4.9 ± 0.8 × 10^–5W (m K²)^–1 at ~600 K. Advances in the application of Magnéli phases are mostly hindered by synthetic and processing challenges, especially when metastable and nanostructured materials such as V6O11 are involved. Here, this study gives insight into the complications of SPS-assisted synthesis of complex oxide materials, provides new information about the thermal and electrical properties of vanadium oxides at high temperatures, and supports the concept of reducing the thermal conductivity of materials with structural building blocks such as crystallographic shear (CS) planes.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1436798
• Journal Information: Inorganic Chemistry, Vol. 57, Issue 3; ISSN 0020-1669
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
thermal conductivity
oxides
physical and chemical processes
electrical conductivity
phase transitions