Engineering of copper sulfide-based nanomaterials for thermoelectric application

In the context of diminishing energy resources and worsening greenhouse effect, thermoelectric materials have great potential for sustainable development due to their green and environmentally friendly characteristics. Among inorganic thermoelectric materials, copper sulfide compounds have greater potential than others due to their abundant element reserves on Earth, lower usage costs, non-toxicity, and good biocompatibility. Compared to organic thermoelectric materials, the "phonon liquid-electron crystal" (PLEC) feature of copper sulfide compounds makes them have stronger thermoelectric performance. This review summarizes the latest research progress in the synthesis methods and thermoelectric modification strategies of copper sulfide compounds. It first explains the importance of the solid-phase method in the manufacture of thermoelectric devices, and then focuses on the great potential of nanoscale synthesis technology based on liquid-phase method in the preparation of thermoelectric materials. Finally, it systematically discusses several strategies for regulating the thermoelectric performance of copper sulfide compounds, including adjusting the chemical proportion of Cu_2-xS and introducing element doping to regulate the crystal structure, phase composition, chemical composition, band structure, and nanoscale microstructure of copper sulfide compounds, and directly affecting ZT value by adjusting conductivity and thermal conductivity. In addition, it discusses composite engineering based on copper sulfide compounds, including inorganic, organic, and metal compounds, and discusses tri-component compounds derived from sulfide copper. Finally, it discusses the main challenges and prospects of the development of copper sulfide-based thermoelectric materials, hoping that this review will promote the development of copper sulfide-based thermoelectric materials.