Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA;Ames Laboratory, Department of Energy, Iowa State University, Ames, IA 50011, USA;Department of Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, CA 92093, USA;Buildings and Thermal Sciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA;Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, IN 46556, USA;Ames Laboratory, Department of Energy, Iowa State University, Ames, IA 50011, USA;Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA;Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011, USA;Department of Mechanical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221, USA;Department of Mechanical and Aerospace Engineering, University of California-San Diego, La Jolla, CA 92093, USA
Abstract:
Anisotropy and inhomogeneity are ubiquitous in spark plasma sintered thermoelectric devices. However, the origin of inhomogeneity in thermoelectric nanocomposites has rarely been investigated so far. Herein, we systematically study the impact of inhomogeneity in spark plasma sintered bismuth antimony telluride (BiSbTe) thermoelectric nanocomposites fabricated from solution-synthesized nanoplates. The figure of merit can reach 1.18, which, however, can be overestimated to 1.88 without considering the inhomogeneity. Our study reveals that the inhomogeneity in thermoelectric properties is attributed to the non-uniformity of porosity, textures and elemental distribution from electron backscatter diffraction and energy-dispersive spectroscopy characterizations. This finding suggests that the optimization of bulk material homogeneity should also be actively pursued in any future thermoelectric material research.
