Berlin 2015 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 37: Thermoelectric Materials (organized by DS)

TT 37.6: Talk

Tuesday, March 17, 2015, 10:45–11:00, H 0111

Enhanced thermoelectric efficiency of p-type Half-Heuslers by intrinsic phase separation and carrier concentration optimization. — •Elisabeth Rausch^1,2, Claudia Felser², and Benjamin Balke¹ — ¹Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Mainz, Germany — ²Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany

State of the art p-type Half-Heusler compounds (space group F43m) for thermoelectric applications are found in the MCoSb_0.8Sn_0.2 (M = Ti/Zr/Hf) system. The outstanding properties are achieved by a nanostructuring approach via ball milling followed by a rapid consolidation method. We, herein report on a alternative approach to reduce the thermal conductivity, which is by an intrinsic phase separation. A optimum ratio of Ti to Hf in combination with an adjustment of carrier concentration via Sn substitution lead to a record thermoelectric figure of merit ZT = 1.15 for Ti_0.25Hf_0.75CoSb_0.85Sn_0.15. Our study is complemented by a long-term stability test under thermal cycling conditions in the interesting temperature range for automotive applications.