This month has been reported in Nature the thermoelectric material with the highest efficiency (ZT=2.6 at 923 K) so far: SnSe. The main reason for the high ZT is the ultralow thermal conductivity (0.25 W/mK) which is similar to that of polymers. This breakthrough has been achieved at the Mercoury Kanatzidis' Group in Northwestern University (USA).
SnSe is probably the world’s least thermally conductive crystalline material, so it can get hot on one side while keeping cold the other side. In addition, it holds a high Seebeck coefficient (around 0.4 mV/K). These results demonstrate that a high efficiency can be realized in simple layered, anisotropic and anharmonic systems, offering an alternative to the most-followed strategy of nanostructuring in order to improve the efficiency of thermoelectrics.
