Remarkably high thermoelectric performance of Cu2−xLixSe bulks with nanopores
Cu2Se is a p-type semiconducting compound that possesses excellent thermoelectric properties which exhibit great potential for practical applications. In recent years, there have been many ways to improve thermoelectric properties. Reducing the thermal conductivity is a very effective way to obtain high performance thermoelectric materials. In this study, a series of Cu2−xLixSe (x = 0, 0.01, 0.02 and 0.03) polycrystalline bulk samples were successfully prepared by hot-pressing the nanopowders made by hydrothermal synthesis to investigate the doping effects of Li on the phase structure, microstructure and thermoelectric properties of Cu2Se. Compared with the Li-free Cu2Se, the introduction of Li element increases the Seebeck coefficient. Importantly, both nanopores and Li substitution were observed which can reduce κLvia increased scattering phonons. At 973 K, the Cu1.98Li0.02Se sample presented an excellent ZT of 2.14.