Ordered-Disordered Material as High Efficiency Thermoelectrics
Final Report Abstract
Ordered-disordered materials show immense potential in various applications. Clear examples include layered structures with loosely bonded intercalations, superionic conductors, and rotating organic molecular units confined in inorganic cages, which are beneficial for thermoelectrics, solid state batteries, fuel cells, and photovoltaics. Understanding heat transfer process in ordered-disordered materials is the first step for structural optimization and material design. However, theoretical studies of thermal transport in these new materials are challenging due to the failure of the standard picture of atoms vibrating around fixed equilibrium positions. For instance, the conventional phonon transport theory is based on near equilibrium anharmonicity and thus fails to treat frustrated energy landscape with significant movement of ions or subsystem. The overarching goal of this project is to elucidate mechanisms of the concomitant and competing solid-“liquid” energy transport (inherently entangled heat and ion transport) in some technologically pertinent materials – weakly bonded layered thermoelectrics and lithium ion batteries. Some critical scientific questions, such as selective breakdown of transverse acoustic phonon modes, abnormal temperature dependent thermal conductivity, and inherent correlation between thermal and ion transport, have been creatively investigated. The proposed project is expected to bring a new research era for two-channel heat transfer and discover new chapter for undergraduate and graduate heat transfer courses. The study performed herein will not only provide a perspective into the various materials challenges that limit the performance and stability of solid-state batteries and ion-conducting thermoelectrics, but also be of both fundamental significance and technological interest to the broader context of ordereddisordered materials. The knowledge gained through this project will facilitate the process of designing new structures and materials for a large range of technological needs, such as thermoelectric energy conversion, hydrogen/CO2 storage, fuel cells, and solar energy conversion (photovoltaics). The project topic is timely in that it aims to addressing the rapidly growing thermal control demands of large industrial sectors, which call for fundamentally different approaches to novel thermal solutions that could overcome barriers faced by the current technologies.
Publications
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"Thermal Transport Crossover from Crystalline to Partial-Crystalline Partial-Liquid State", Nature Communications, 9, 4712 (2018)
Yanguang Zhou, Shiyun Xiong, Xiaoliang Zhang, Sebastian Volz, and Ming Hu
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"Two-Channel Thermal Transport in Ordered– Disordered Superionic Ag2Te and its Traditionally Contradictory Enhancement by Nanotwin Boundary", Journal of Physical Chemistry Letters, 9, 5704 (2018)
Biyao Wu, Yanguang Zhou, and Ming Hu
