Method for reducing thermal conductivity of bismuth telluride polycrystal lattice

Abstract

The invention relates to a method for reducing thermal conductivity of a bismuth telluride polycrystal lattice and belongs to the technical field of energy materials. According to the method, bismuth telluride powder is prepared in a mechanical alloying method and is mixed with Te with an additional mass ratio of 5-30% and then undergoes secondary ball milling, and powder with bismuth telluride and simple substance tellurium evenly mixed with each other is obtained. The mixed powder is placed in a graphite die, and a spark plasma sintering process is adopted to perform sintering for 0-30 min at 450-580 DEG C to prepare bismuth telluride polycrystalline blocks. In the spark plasma process, since Te has a low melting point and is liquified completely and since Te is extruded out of the graphite die under the pressure effect, plenty of dislocations are reserved in bismuth telluride blocks, and the lattice thermal conductivity of a material is reduced through introduction of plenty of dislocations. The method is simple in process and easy to operate, and the thermal conductivity is reduced vey obviously.

Description

technical field [0001] The invention belongs to the technical field of energy materials, in particular to a method for reducing the thermal conductivity of bismuth telluride polycrystalline lattice, and to mechanical alloying and discharge plasma sintering technologies. Background technique [0002] With the continuous development of social economy, environmental and energy issues are paid more and more attention by human beings. Thermoelectric materials can directly realize the mutual conversion of heat energy and electric energy. Thermoelectric devices are pollution-free, zero-emission, light in structure, small in size and long in life, and are increasingly attracting people's attention. Thermoelectric modules with thermoelectric devices as core components have broad application prospects in semiconductor refrigeration and thermoelectric batteries. In the competition with conventional refrigeration methods and traditional power sources, the key to the wide application of...

AI Technical Summary

Problems solved by technology

However, there are currently problems in reducing the thermal conductivity of the bismuth telluride lattice: nanocrystalline bismuth telluride reduces the thermal conductivity of the lattice by increasing the grain boundaries, but the crystal grains are easy to grow during repeated heating and use; The method of introducing nano-precipitates to reduce the thermal conductivity of the lattice, on the one hand, the precipitates also scatter electrons, on the other hand, the thermal stability of nano-precipitates has been controversial; the thermal conductivity of bismuth telluride thermoelectric materials prepared by conventional methods about 0.5

Images