• Kruszewski, Mirosław
• Grzonka, Justyna
• Zybała, Rafał
• Schmidt, Maksymilian
• Kamińska, Paulina
• Pietrzak, Katarzyna
• Ciupiński, Łukasz

Abstract

In this work, we present a new fabrication method of thermoelectric nanomaterials using Pulsed Plasma in Liquid (PPL)with a low-energy spark discharge. Thermoelectric (TE) materials can be used for direct energy conversion from heat intoelectricity. They are of particular interest as a result of enabling both clean energy transformation and waste heat energyharvesting. The efficiency of the conversion process depends on the Carnot cycle and the material’s properties, described by thethermoelectric figure-of-merit (ZT). This parameter is based on electrical conductivity, Seebeck coefficient and thermalconductivity. One can increase the ZT value by reducing the thermal conductivity e.g. through the nano-structuring of TEmaterials and, at the same time, conserving their electrical properties. CoSb3, which is a state-of-the-art TE material from theskutterudite family known as a narrow-band gap semiconductor with a parabolic bottom of the conduction band, was studied inthe present work.Binary skutterudite CoSb3 polycrystalline ingots were synthesized by a direct fusion technique from pure elements. Thedensified materials with a cylindrical shape were used as substrates in the fabrication process of CoSb3 nanoparticles via themodified Pulse Plasma in Liquid method. The nanopowders were consolidated using rapid Spark Plasma Sintering (SPS) with theprocessing time in minutes. X-ray diffraction (XRD), scanning electron microscopy (SEM/EDS) and scanning transmissionelectron microscopy (STEM) were used to characterize the synthesized powders and sinters. Thermal conductivity wasdetermined by the laser flash technique (LFA). Electrical properties such as resistivity and Seebeck coefficient were measured bythe four probe technique, as a function of temperature.

Topics

• nanoparticle
• impedance spectroscopy
• resistivity
• scanning electron microscopy
• x-ray diffraction
• semiconductor
• Energy-dispersive X-ray spectroscopy
• thermal conductivity
• electrical conductivity
• sintering