Enhanced thermoelectric performance of Cu1.85Se doping with Mg via a low-temperature molten salt electrolysis method

Abstract

This study demonstrates a low-temperature molten salt electrolysis (MSE) strategy for synthesizing Cu_1.85Se and Mg-doped Cu_1.85Se with enhanced thermoelectric performance. Structural analyses (XRD/SEM/EDS) confirm that Mg doping induces lattice defects while maintaining material homogeneity. The Mg-doped sample exhibits a 7.4 times increase in ZT (0.35 at 500 K) compared to pristine Cu_1.85Se, attributed to synergistic optimization of the electron and phonon transport. Mg doping boosts the Seebeck coefficient by 112% through carrier concentration modulation and reduces lattice thermal conductivity by 69% via intensified phonon scattering at 500 K. These results highlight the dual advantages of active metal doping (particularly Mg) in decoupling electron–phonon interactions and the unique capability of MSE for defect engineering in thermoelectric materials, offering a new approach for developing high-performance thermoelectric materials.