Increased thermoelectric efficiency raises energy harvest prospects

Technology News |
By Peter Clarke

The study observed record-high conversion efficiency of 11.3 percent, which is 60 percent better than commercially-available materials prepared by the zone melting method. The result opens up the prospect of low-maintenance solid-state refrigeration, zero-carbon power generation and wearable devices powered by body heat, according to the researchers.

“The decoupling of electronic (electron-based) and thermal (phonon-based) transport will be a game-changer in this industry,” said Professor Xiaolin Wang, who led the study.

The research focused on the Seebeck and Peltier effects in bismuth telluride‐based thermoelectric materials, which are capable of direct and reversible conversion of thermal to electrical energy. An ongoing challenge of thermoelectric materials is that in most cases, an improvement in a material’s electrical conductivity means a worsening of thermal conductivity, and vice versa.

The researchers showed that by including a small amount of nanoscale particles of amorphous boron into the p‐type Bi0.5Sb1.5Te3, a record high conversion efficiency figure of merit of 1.6 at 375 K is achieved. Amorphous nano boron particles were introduced using the spark plasma sintering (SPS) method. The research showed that the boron inclusions created a high density of nanostructures and dislocations leading to a significant reduction of thermal conductivity and improved charge transport. This could be a boon to the generation of power from waste heat.

Ultra-High Thermoelectric Performance in Bulk BiSbTe/Amorphous Boron Composites with Nano-Defect Architectures was published in Advanced Energy Materials in September 2020, and selected as the cover story for the November edition.

The work was done under the auspices of the Centre for Future Low-Energy Electronics Technologies (FLEET) at the University of Woollangong, FLEET is a collaboration of over a hundred researchers, seeking to develop ultra-low energy electronics to face the challenge of energy use in computation.

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