Abstract:
Thermoelectrics enable direct conversion of waste heat into useful electricity; therefore, they can play a crucial role in reducing carbon dioxide emissions and improving thermal management to create a sustainable society. There have been several important breakthroughs in enhancing the figure of merit (zT) of thermoelectric materials in this century. However, thermoelectric modules and technologies are used only in niche applications. The advanced thermoelectric materials have not yet been fully explored for module development, making a big technological valley between materials and module development. This talk focuses on recent challenges in bridging the technological valley between materials development, module fabrication, and evaluation methods for high-temperature thermoelectric power generation.
In PbTe and colusites (Cu and S-based systems), we have demonstrated high zT in the materials and corresponding high conversion efficiency in the modules [1,2,3,4]. For PbTe, the material’s zT was dramatically enhanced through nanostructuring and controlled doping. For colusites, material’s zT was dramatically enhanced by chemical composition tuning. In both systems, the improved electrical and thermal contact resistances between thermoelectric materials and electrodes, enhanced mechanical strength, and the optimized configuration of thermoelectric elements and modules led to high conversion efficiency and improved reliability of high-temperature power generation in the modules.
It is also important to develop technologies for reliably and accurately evaluating the power generation characteristics of the modules. In this work, interlaboratory testing was carried out using a mechanically durable Ni-based alloy module in characterization facilities developed the National Institute of Advanced Industrial Science and Technology (AIST), the German Aerospace Center (DLR), and so on to understand the differences in the evaluation methods from each other [5].
The PbTe-based materials and module were developed together with Prof. M. G. Kanatzidis of Northwestern University and Argonne National Laboratory. The colusites-based materials and module were developed together with Dr. K. Suekuni of Kyushu University, Dr. Y. Bouyrie of AIST, Dr. R. Chetty of AIST, and Dr. E. Guilmeau of CRISMAT. Interlaboratory testing performed together with P. Ziolkowski of DLR, Prof. E. Muller of DLR, Dr. R. Chetty of AIST, Dr. K. Okawa of AIST, Dr. Y. Amagai of AIST, and Dr. R. Funahashi.
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