Low temperature sintering to reduce thermal conductivity of a metal oxide thermoelectric material Stephanie Mudd The University of Sheffield, UK Thermoelectric materials have the potential to ease the demand on fossil fuels by recuperating the waste heat released on mass during energy conversion processes. Foreman et al. report the amount of energy lost as waste heat as close to two thirds of the total energy we convert from primary energy resources. [1] The current barriers for wide scale use of thermoelectric devices are cost and efficiency: efficient materials like bismuth telluride are too costly, metal oxides are a much cheaper, less toxic alternative to tellurides but their efficiencies, particularly in the n-type materials, are much lower. However, in 2016 Zhilun Lu et al. [2] published the highest ZT (figure of merit) n-type metal oxide to date: La 0.15 Sr 0.775 TiO 3-x . A draw-back of most metal oxides is their high thermal conductivity, which decreases the thermoelectric efficiency. By reducing the grain size using our novel cold sintering process we can not only reduce the energy consumption of the ceramic sintering process but reduce its thermal conductivity simultaneously - potentially pushing the figure of merit even higher. This novel process couples ionic liquid synthesis and a modified version of the recently proposed Reactive Cold Sintering Method to synthesise and retain small grains within a dense final product. [3] References 1. C. Forman, I. K. Muritala, R. Pardemann and B. Meyer, Renew. Sustain. Energy Rev., 2016, 57, 1568–1579 2. Z. Lu, H. Zhang, W. Lei, D. C. Sinclair and I. M. Reaney, Chem. Mater., 2016, 28, 925–935 3. R. Boston, J. Guo, S. Funahashi, A. L. Baker, I. M. Reaney and C. A. Randall, RSC Adv., 2018, 8, 20372–20378.
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