High-performance thermoelectric Cu2Se nanoplates through nanostructure engineering

As one of promising thermoelectric materials with intrinsic high figure of merit (ZT), Cu2Se provides opportunities to tackle the global energy crisis via converting waste heat into electricity. Here, β-phase Cu2Se nanostructures were synthesized using a facile and large-scale solvothermal method. After sparking plasma sintering, the resultant Cu2Se pellets show outstanding thermoelectric properties with an ultra-low lattice thermal conductivity (as low as ~0.2 W m−1 K−1) that resulted in a recorded high ZT of 1.82 at 850 K. Through detailed structural investigations, high-densities small-angle grain boundaries with dislocations have been found in sintered Cu2Se pellets through nanostructure engineering, which results in additional phonon scattering to reduce the lattice thermal conductivity. This study provides an important approach to enhance thermoelectric performance of potential thermoelectric materials.