High thermoelectric performance and low thermal conductivity in Cu_(2-x)Na_xSe bulk materials with micro-pores

摘要

Cu(2)Sehas been considered as a promising thermoelectric material due to its unique structure and excellent performance. Herein, a series of Cu2-xNaxSe (x=0, 0.01, 0.02, 0.03, and 0.04) polycrystalline samples were synthesized by combining hydrothermal synthesis and hot pressing to investigate the effects of Na-doping on the microstructure and thermoelectric properties of Cu2Se. Compared with the pristine Cu2Se, the Na-doping introduces numerous micro-pores that can optimize the thermal transport performance by strong phonon scattering effects of interfaces between the micro-pores and grains. The doped samples have excellent electrical properties and low thermal conductivity. The maximum value of ZT=2.1 is obtained at 973K for the Cu1.96Na0.04Se sample with nominal composition. The results confirm that introducing Na into Cu2Se is an effective and convenient strategy to improve the thermoelectric performance of the Cu2Se alloy by decreasing the lattice thermal conductivity.