SEEBECK EFFECT IN COMPLEX FLUIDS & MAGENTA PROJECT (MAGNETIC NANOPARTICLE BASED LIQUID ENERGY MATERIALS FOR THERMOELECTRIC APPLICATIONS)

Thermoelectric (TE) materials that are capable of converting heat into electricity have been considered as one possible solution to recover the low-grade waste-heat (from industrial waste-stream, motor engines, household electronic appliances or body-heat). Solid semiconductor-based TE-modules were the first to enter the commercial application, and they still dominate the TE-market today. Despite their technical robustness including long life-time, simple use involving no moving parts, TE-technology has long been limited to low-power applications due to their poor efficiency. Closely following the rise of ‘nanotechnology’ in the 1980’s - 90’s, there has been a huge increase in the TE materials research in the past 20 years, which has led to some remarkable improvements in thermal-to-electric energy conversion capacity. However, even the most “promising” materials have not yet reached the minimum ZT requirements. Furthermore, solid TE-materials suffer from a variety of practical obstacles such as small sizes, substantial production costs and the use of scarce and/or toxic raw materials, precluding them from wide-scale applications. Clearly, a technological breakthrough in TE-materials research is needed in order to make the thermoelectric technology environmentally friendly and economically viable for its future use. MAGENTA is a 4-year research & innovation project that aims at bringing a paradigm change in TE-technology by exploiting the magneto-thermoelectric (MTE) property of ionic-liquid (IL) based ferrofluids (FF), i.e., colloidal dispersions consisting of magnetic nanoparticles (MNPs) in non-magnetic ionic liquids. Magnetic nanoparticles are, as the name suggests, a class of nanoparticles (less than 1 mm in diameter) made of magnetic elements such as iron and nickel and their alloys and chemical compounds. They are used in a plethora of technological fields from biomedicine to data storage. However, their use in energy applications remains quite limited so far. Ionic liquids (IL), on the other hand, are enjoying substantial attention in several areas of energy research including thermoelectricity in recent decades. As a thermoelectric material, ILs present many promising features such as high electrical conductivity, large temperature and electrochemical windows, low vapour pressure and toxicity, and raw material abundance. In this presentation, I will discuss MAGENTA’s scientific motivations (how to produce thermoelectric voltage and current using IL based ferrofluids), the methodologies to be used and the project objectives; i.e., 1) to provide founding knowledge of novel MTE phenomena in IL based ferrofluids, and 2) to build application-specific MTE prototypes with tailor-made IL-FFs for their use in targeted industrial sectors (cars and portable electronics). Some encouraging preliminary results on liquid thermoelectric materials obtained by the project partners will also be presented.