Method of producing thermoelectric material

Abstract

A thermoelectric material is provided. The material can be a grain boundary modified nanocomposite that has a plurality of bismuth antimony telluride matrix grains and a plurality of zinc oxide nanoparticles within the plurality of bismuth antimony telluride matrix grains. In addition, the material has zinc antimony modified grain boundaries between the plurality of bismuth antimony telluride matrix grains.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. patent application Ser. No. 13 / 117,286 filed May 27, 2011, the contents of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]This invention relates to materials having thermoelectric properties and to thermoelectric devices.BACKGROUND OF THE INVENTION[0003]A thermoelectric device can be used to obtain electrical energy from a thermal gradient (for example, a thermoelectric generator using the Seebeck effect), or to generate a thermal gradient from electrical energy (for example, a thermoelectric refrigerator using the Peltier effect). The discussion below is directed to the Seebeck effect, but the general concepts also apply to applications of the Peltier effect.[0004]A typical thermoelectric device is built up from several unicouples, which are typically pairs of thermally conductive p-type (P) and n-type (N) semiconductors. These unicouples are connected electricall...

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Problems solved by technology

Increasing ZT is difficult because the three parameters S, σ, and k are all related to the free carrier concentration and are usually not independent.

However, these approaches do not provide a simple approach to making large-scale, low-cost thermoelectric devices.

Conventional semiconductor device fabrication methods are unsuitable for manufacturing bulk samples, and are often expensive.

In automobiles, about 70 percent of energy derived from fuel is lost to waste heat and engine cooling.

Only a small proportion of energy provided by fuel combustion is used, and a large amount of thermal energy is thrown away.

Recovery of waste thermal energy is a big challenge in automotive industries due to the increasing energy crisis.

However, direct thermal to electric conversion (DTEC) technology currently faces two major challenges: low conversion efficiency and insufficient power density.

However, as of yet no process has been developed to determine if there is and / or which optimum range of such factors can provide a thermoelectric material with an improved ZT.

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