Thermoelectric materials synthesized by self-propagating high temperature synthesis process and methods thereof

A method of preparing a thermoelectric material, comprising:

• 1) weighing powders of reactants according to an appropriate stoichiometric ratio, mixing the powders in an agate mortar, and cold-pressing the powders into a pellet;
• 2) sealing the pellet in a silica tube under a pressure of 10−3 Pa, initiating a self-propagating high temperature synthesis (SHS) by point-heating a portion of the pellet wherein, once the SHS starts, a wave of exothermic reactions passes through the remaining portion of the pellet, cooling down the pellet after reaction in air or quenched in salt water to obtain a cooled-down pellet;
• and
• 3) crushing the cooled-down pellet obtained in step 2) into powder, and sintering the powder with plasma activated sintering (PAS) to form a bulk material,
• wherein the reactants include Co, M, Sb, and Te powders, M is Fe or Ni, the stoichiometric ratio is Co:M:Sb:Te=4−e:e:12−f:f, where 0≤e≤1.0, 0≤f≤1.0, the cooled-down pellet obtained in step (2) contains Co4-eMeSb12-fTef;
• and parameters of the PAS include a reaction temperature of 650° C. with a heating rate of 100° C./min and a pressure of 40 MPa for 8 min, a final product is a CoSb3 based thermoelectric material.