Abstract/Summary

Sulfides are attractive candidates for thermoelectric energy recovery in the mid-range of temperatures, including temperatures where the highest proportion of industrial waste heat is released. The high polarizability of the sulfide anion leads to significant bonding anisotropy and the adoption of low-dimensional structures. Such structures offer opportunities to enhance the Seebeck coefficient and reduce the lattice contribution to thermal conductivity. The polarizable sulfide anion also promotes cation diffusion, which at elevated temperatures can lead to the emergence of a liquid-like cation sub-lattice, within a rigid anion matrix, conferring the characteristics of a phonon-glass-electron-crystal. A series of sulfides is described, in which these features of the sulfide anion are exploited to produce high thermoelectric performance. This includes materials derived from transition-metal disulfides, shandite and binary and ternary copper sulfides.