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          Institute: MPI für Chemische Physik fester Stoffe     Collection: publications 2013     Display Documents

ID: 670769.0, MPI für Chemische Physik fester Stoffe / publications 2013
Using crystallographic shear to reduce lattice thermal conductivity: high temperature thermoelectric characterization of the spark plasma sintered Magnéli phases WO2.90 and WO2.722
Authors:Kieslich, G.; Veremchuk, I.; Antonyshyn, I.; Zeier, W. G.; Birkel, C. S.; Weldert, K.; Heinrich, C. P.; Visnow, E.; Panthofer, M.; Burkhardt, U.; Grin, Y.; Tremel, W.
Date of Publication (YYYY-MM-DD):2013-10-28
Title of Journal:Physical Chemistry Chemical Physics
Issue / Number:37
Start Page:15399
End Page:15403
Review Status:not specified
Audience:Not Specified
Abstract / Description:Engineering of nanoscale structures is a requisite for controlling the electrical and thermal transport in solids, in particular for thermoelectric applications that require a conflicting combination of low thermal conductivity and low electrical resistivity. We report the thermoelectric properties of spark plasma sintered Magneli phases WO2.90 and WO2.722. The crystallographic shear planes, which are a typical feature of the crystal structures of Magneli-type metal oxides, lead to a remarkably low thermal conductivity for WO2.90. The figures of merit (ZT = 0.13 at 1100 K for WO2.90 and 0.07 at 1100 K for WO2.722) are relatively high for tungsten-oxygen compounds and metal oxides in general. The electrical resistivity of WO2.722 shows a metallic behaviour with temperature, while WO2.90 has the characteristics of a heavily doped semiconductor. The low thermopower of 80 mu V K-1 at 1100 K for WO2.90 is attributed to its high charge carrier concentration. The enhanced thermoelectric performance for WO2.90 compared to WO2.722 originates from its much lower thermal conductivity, due to the presence of crystallographic shear and dislocations in the crystal structure. Our study is a proof of principle for the development of efficient and low-cost thermoelectric materials based on the use of intrinsically nanostructured materials rather than artificially structured layered systems to reduce lattice thermal conductivity.
External Publication Status:published
Document Type:Article
Communicated by:Ina Werner
Affiliations:MPI für chemische Physik fester Stoffe
Identifiers:ISI:000323727800017 [ID No:1]
ISSN:1463-9076 [ID No:2]
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