PbSnSe2-based polycrystalline block thermoelectric material and preparation method and application thereof

The invention provides a PbSnSe2-based polycrystalline block thermoelectric material as well as a preparation method and application of the PbSnSe2-based polycrystalline block thermoelectric material. The chemical general formula of the PbSnSe2-based polycrystalline block thermoelectric material is PbSn1-xInxSe2, and x is greater than or equal to 0 and less than or equal to 0.1. The PbSnSe2-based polycrystalline block thermoelectric material is prepared by adopting a high-temperature melting method and a discharge plasma sintering technology after the raw materials with the purity of 99.9999% are selected and weighed in proportion, the materials are easy to obtain, the preparation process is simple, the use of the lead element is reduced, the environmental pollution can be reduced, and meanwhile, the dependence on the tellurium element is reduced. Wherein the N-type PbSnSe2-based polycrystalline block thermoelectric material is obtained by doping a high-valence element indium at a tin site on the basis of an