International. Every time we convert energy from one form to another, some of that energy is lost as heat. Trying to recover that energy efficiently is very difficult once it is lost in the environment.
Thermoelectric devices can change thermal energy into electricity and vice versa. But to capture heat energy efficiently, these devices usually need to work at high temperatures with a large temperature difference.
Now, researchers focused on Japan's University of Tsukuba have developed a new type of thermoelectric system that can take advantage of small energy differences at low temperatures. They recently reported their results in Applied Physics Express.
"Thermoelectric batteries, like ours, have been proposed before, but they have been based on liquid cells, which are not practical for real-world applications. We created a thin-film device that works on the same principle but with two types of solid redox materials that produce a change in the potential difference in the cell during a heating and cooling cycle," Takayuki Shibata says first.
In the device, changing the temperature alters the ability of the different layers in the device to retain electrons. If one layer has a higher affinity for electrons than another, this creates a potential difference. The flow of electrons from one layer to the other can be harnessed to do the job as the cell discharges, in the same way that a normal battery works.
The researchers tested their devices to collect residual thermal energy near room temperature. His device produced an electrical energy of 2.3 meV per heat cycle between around 25 and 50 degrees Celsius. This result reflects an efficiency of around 1.0%, although the theoretical maximum for this device should be around 8.7%.
Correspondent Yutaka Moritomo says, "We still have some work to do to improve efficiency as we hope these problems will be overcome by optimizing anode and cathode materials. Importantly, we have shown that solid-state thermoelectric batteries are viable and our film deposition method could be extended to large areas. This technology offers realistic prospects for large-scale heat energy recovery, which could help a range of industries become more efficient."
Source: https://www.sciencedaily.com/
