Researchers Synthesize Barium Cobalt Oxide Thermoelectric Converter, Potential Source of Energy Conservation

Waste heat is an extremely promising energy conservation source, and reuses it by converting this heat into electricity, a process known as thermoelectric conversion.

As indicated in a EurekAlert! report, while these are quite effective, they are costly and, in most cases, use toxic materials. Both factors have resulted in such converters being of limited function.

One of the substitutes is oxide-based thermoelectric materials, although the main drawback these are suffering from is the absence of evidence of their stability at high temperatures.

The research team, led by Professor Hiromichi Ohta at the Research Institute for Electric Science at Hokkaido University, has synthesized a barium cobalt oxide thermometer converter that's reproducibly sturdy and effective at temperatures as high hot as 600 degrees Celsius.

Effectiveness of Thermoelectric Conversion

Essentially, thermoelectric conversion is compelled by the Seebeck impact; when there is a difference in temperature throughout a conducting material, an electric current is produced.

Nonetheless, thermoelectric conversion's efficacy relies on a figure known as the thermoelectric figure of merit ZT.

Historically, as indicated in the study published in ACS Applied Materials & Interfaces, oxide-based converters had a low ZT. However, recent research has shown many candidates with high ZT, although their stability at high temperatures was not well recorded.

The group of Hiromichi Ohta has been working on layered cobalt oxide films for more than 20 years. In this research, the team sought to investigate the thermal and chemical stability of the films and measure their ZT values at such a high temperature.

Cobalt Oxide Films

The study investigators tested cobalt oxide films layered with sodium, strontium, calcium, or barium, examining their structure, thermal conductivity, and resistivity.

As a result, the study investigators discovered that of the four variants, the barium cobalt oxide layered film could retain its stability regarding structural integrity and electrical resistivity at temperatures as high as 600 degrees Celsius.

To compare, the sodium, sodium- and calcium cobalt oxide films were only stable until 350 degrees Celsius, and the strontium cobalt oxide film was stable up to 450 degrees Celsius.

The barium cobalt oxide film's barium cobalt increased with the temperature, reaching ~0.55 at 600 degrees Celsius, compared to specific commercially thermoelectric converters.

According to Himorichi Ohta, a similar Bioengineer.org report specified, their research has revealed that barium cobalt oxide films would be ideal candidates for high-temperature thermoelectric conversion devices. Additionally, he added, they are environment friendly, providing potential for wide employment.

Thermoelectric Converter

As specified in a study published in Nano Energy, thermoelectricity, green technology that can convert massive free thermal energy to electricity minus time and geographical limitations, is essential for bright future energy to control global warming.

In recent decades, numerous efforts have been made to develop thermoelectric (TE) materials and their devices for various applications.

Here, the most recent progress of thermoelectric materials and devices is summarized. Several strategies for enhancing the performance of thermoelectric materials via regulating carriers and phonons are also described in this report.

Aside from the common heat source from natural, industrial, radioisotope, human and solar energy harvesting in various methods, the attractive cooling technology can offer a cold source for thermoelectric devices to produce electricity.

Related information about thermoelectric efficiency is shown on YedaCenter's YouTube video below:

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