P-type high-performance thermoelectric material with reversible phase change, and preparation method therefor

A method for preparing the P-type high-performance thermoelectric material with the reversible phase transition, characterized in that a chemical composition of the thermoelectric material is Cu2Se1-xIx, wherein 0<x≤0.08, and wherein the thermoelectric material has a sandwich-shape layered structure with a thickness of 20˜50 nm, the method comprising:

• weighing elemental copper metal, elemental selenium metal, and cuprous iodide at a mole ratio of (2−x):(1−x):x as raw materials and encapsulating the raw materials under a vacuum;
• gradiently heating the raw materials by first heating the raw materials to 650˜700° C. at a heating rate of 2.5˜5° C./min and keeping them thereat for 1˜2 hours, then further heating the raw materials to 1150˜1170° C. at a heating rate of 0.8˜2° C./min and keeping them thereat for 12˜24 hours for melting;
• gradiently cooling the melt to 600˜700° C. and keeping it thereat for 5˜7 days for annealing treatment;
• furnace-cooling the melt to room temperature;
• and
• heating the room temperature melt to 400˜450° C. for pressure sintering.