An overview of advanced thermoelectric materials

An overview of advanced thermoelectric materials A large amount of our useful energy is being lost as waste heat.Much of this wasted heat is of high grade and occurs in a distributed fashion.Therefore is a compelling need for highperformance thermoelectric materials that can directly and reversibly convert heat to electrical energy [1].In the past decades, the exploration of high-performance thermoelectric materials has attracted ever-increasing attention both from the energy and environmental fields and with a view to commercial applications.Considering the structural, electronic and compositional complexity of thermoelectric materials, further development would benefit greatly from close collaborations across a large scientific community of chemists, physicists and materials scientists [2,3].Globally, some groups have been at the vanguard of development in the field of thermoelectrics.We believe that these advances deserve to be highlighted to the broad readers of Journal of Materiomics.For this purpose, we compiled this thermoelectric special issue, which involves high-ZT PbTe, SnTe, Cu 2 Se, oxychalcogenides (BiCuSeO), Cu 2 CdSnSe 4 , MnTe, half-Heusler, Skutterudites, caged-free Cu-based diamond-like compounds, and Mg 2 Sn 0.75 Ge 0.25 etc.The aspects of this special issue cover strategies of electronic band structures engineering, microstructure designing, nanostructuring, and the first-principles calculations, etc.Many of the key discoveries in thermoelectric materials have been brought forth by fundamental understandings gained from the first-principles investigations.Density functional theory (DFT) provides a framework in which band structure predictions, phase diagrams enabled by cluster expansion methods, and the phase stability of unknown compounds can be calculated.Half-Heusler alloys are an exciting class of thermoelectric materials that have shown great improvements in the thermoelectric figure of merit, ZT, during the past 15 years.Recent theoretical work has been summarized and reviewed by C. Uher et al. [4].Understanding and manipulating of the band structures are important in designing high-performance thermoelectric materials, i.e., the band convergence, the conductive network, dimensionality reduction and high-throughput material screening.